Heidi Hewett's Blog

AutoCAD 3D Online Course

If you are interested in learning about the 3D modeling tools in AutoCAD 2007 and 2008, you can view the Transitioning to 3D with Ease in AutoCAD® 2007 course that I taught at Autodesk University 2006. You'll have to register with AU Online and then log in using your name and password. After you log in, you'll see a link to "View the Screencast" on the right side of the page.

 

If you are creating 3D objects in an older version of AutoCAD, it's well worth you time to check out this newer functionality!

Transitioning from 2D to 3D AutoCAD drawings 116

During this series of posts, I’ve demonstrated many of the AutoCAD 2007 tools and tricks that enable you to transition from 2D drawings to the exciting world of 3D. In these examples, I’ve used a building systems drawing but keep in mind that you can apply all of these tools and tricks to any industry and they are particularly useful for conceptual design. As you become comfortable in the world of 3D and want to get serious about creating 3D models, you should consider Autodesk’s industry-specific 3D modeling applications. Since many of Autodesk’s industry applications use AutoCAD as a foundation, the tools and tricks you learn when transitioning from 2D to 3D AutoCAD will directly apply to these more powerful applications. For example, Autodesk Building Systems enables you to combine the core AutoCAD tools that I’ve shown with automated tools and libraries specifically designed for building systems. You can create 3D building systems models in significantly less time and with more flexibility.

For more information about Autodesk’s industry-specific applications, visit www.autodesk.com and select the appropriate industry.

Transitioning from 2D to 3D AutoCAD drawings 115

Continuing with my “Transitioning from 2D to 3D AutoCAD Drawings” series, I want to copy the current duct to multiple locations and then edit the length and diameter accordingly. Of course, I could draw a new cylinder, repeating the process from my previous post. Or, I could create the ductwork using other methods such as extruding a circle along a path. However, I think copying and editing the cylinders is the most efficient. In older versions of AutoCAD (prior to AutoCAD 2006), editing existing objects was much more difficult and I wouldn’t have even considered this method.

1. Select the cylinder
2. Right-click and choose Copy Selection.
3. Pick the Center of the end of the column to specify the base point.
   
4. Pick the midpoints of each of the ends of the 2D ducts.
   
5. Select a cylinder and then select the length grip.
6. Select the midpoint of the end of the intersecting duct to ensure the cylinder stretches to the middle of the duct.
   
7. Continue editing the existing cylinders by stretching the length or diameter as necessary.
   
   
   You can easily create all the ducts that have the same orientation by repeating this process of copy/grip-edit.
   

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Transitioning from 2D to 3D AutoCAD drawings 114

In my last “Transitioning from 2D to 3D” post, I finished creating the 3D VAV boxes in the HVAC plan. The VAV boxes are currently on the floor. I could move them to the ceiling now, but I decided to wait until I finish creating the ductwork so that I can move the ducts and VAV boxes at the same time.

The ductwork provides the opportunity to use a variety of AutoCAD tools. As usual, there are many different ways to create the same model. I’m going to focus on the methods that enable you to take advantage of the existing 2D geometry using the fewest steps and/or the least amount of thinking.

1. Zoom into an area with ductwork.
   
2. From the Dashboard, choose Cylinder.
3. Pick the midpoint and endpoint of the existing 2D duct to specify the radius of the cylinder. Don’t worry that the cylinder is oriented incorrectly.
4. Drag down a small distance and pick to set the height of the cylinder. You could just as easily drag up. We’ll rotate the cylinder into the proper position and then adjust its height by snapping to existing 2D geometry.
   
5. Select the cylinder and then pass your cursor over the Move grip at the cylinder base. The Move grip tool will display.
6. Select the axis around which you want to rotate. By default, AutoCAD will try to move the selected object along the axis but you can easily switch to Rotate functionality.
   
7. Press the spacebar twice to change from the Move grip tool to the Rotate grip tool.
8. Drag the cursor straight up (along the z polar axis) and pick or enter an angle of 90. If you drew the initial cylinder (step 4) up instead of down, you would do the opposite for this step.
   
9. Select the stretch grip at the end of the cylinder and stretch it to the proper height. The “proper height” depends on what your goal is for the model. If you want the model to be as close to real life as possible, you might want to create each duct segment, including the connectors, as separate objects. However, if you are only concerned with how the model looks, you can reduce steps by combining several “parts” into one. I decided to stretch the duct all the way to center of the large duct to which it will connect. It doesn’t exactly match the real-world parts, but it is quick and will “look” fine after I create the larger duct.
10. Pick the midpoint of the line at the end of the large duct.
    
    I could have “eye-balled” a distance that would extend the small cylinder far enough into the larger cylinder, but if I didn’t stretch far enough, there would be a gap at the intersection of the two cylinders. If I stretched too far, the small duct might protrude to the other side of the large one. By stretching to the middle of the larger duct, I know there won’t be any gaps or excess protrusions.

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Transitioning from 2D to 3D AutoCAD drawings 113

Continuing work on the VAV box from my previous post, I’ll create the extrusions for the primary air inlet and the supply outlet. Since the VAV box is a block, I used REFEDIT to modify the block definition. I’ll continue with my edits from within the REFEDIT command.

1. Press Shift and the middle mouse button to orbit around to the opposite side of the model.
   
2. From the Dashboard, choose Cylinder to draw the protrusion representing the primary air inlet.
3. Pass the cursor over the side of the box to activate it as the current work plane (the DUCS toggle must be on).
4. Pass the cursor over the midpoint of the back line representing the 2D air inlet to acquire the point (midpoint OSNAP and OTRACK must be on).
5. Pass the cursor over the midpoint of the vertical edge of the VAV box.
6. Move the cursor towards the intersection of the two tracking vectors and pick. I could have drawn the cylinder at the midpoint of the 2D geometry and then moved it up like I did in the last post… but this alternate method saves a few steps.
   
7. Pass the cursor over the endpoint of the back line representing the 2D air inlet to acquire the point. I could enter a value for the radius of the cylinder but since I have appropriate 2D geometry, I might as well use my object snaps and tracking.
8. Move the cursor towards the intersection of the horizontal and vertical tracking vectors and pick.
   
9. Drag the cursor out and pick a point (ie. midpoint, endpoint) on the front line of the 2D air inlet. I could enter a value for the height of the cylinder but I wouldn’t want to think that hard! I might as well use the existing 2D geometry!
   
10. From the Dashboard, choose Box to draw the protrusion representing the supply outlet. Instead, I could use the Ctrl-Alt (Presspull) functionality similar to the previous post. This is just another option.
11. Pick opposite endpoints of the existing 2D rectangle.



12. Enter the height of the box. I entered a height of 14. The box representing the supply outlet needs to be vertically centered on the VAV box. I’ll use the MOVE command to move it into position.
13. Select the small box, right-click and choose Move.
14. Pick the midpoint of the back vertical side of the box.
    
15. Pass the cursor over the midpoint of the vertical side of the VAV box.
16. Move the cursor towards the intersection of the horizontal and vertical tracking vectors and pick.
    
17. Erase the 2D geometry.
18. On the Refedit toolbar, choose Save Reference Edits.
    

If you have other versions of similar block definitions, you can repeat these steps to update all of them.

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Transitioning from 2D to 3D AutoCAD drawings 112

In my previous posts, I updated my 2D plan to include 3D objects for the columns and beams, walls, lights and diffusers. To get a better idea of how this drawing looks, I’ll set the conceptual visual style.

The next thing I want to update is the VAV box in the HVAC plan. To make it easier to see the 2D objects that I’m working with, I’ll turn off all the layers except for the 2D walls and HVAC plan. The HVAC plan uses blocks for the 2D VAV box. I’ll edit these block definitions using the REFEDIT tool similar to how I edited the column, beam, lighting, and diffuser blocks. Although the process I’ll use is not drastically different, this block has a few more components, giving me the opportunity to explore different methods.

1. Zoom into a VAV block.
2. Select one of the block references, right-click and choose Edit Block In-place. This launches the REFEDIT command.
3. In the Reference Edit dialog box, choose OK.
4. Press the Ctrl and Alt keys and pick inside the VAV box.
5. Drag the cursor up and pick a point or enter a value for the height. I entered a height of 17.125.
   
6. Press the Ctrl and Alt keys and pick inside the small rectangle representing the induced air outlet.
   
7. Drag the cursor up and pick a point or enter a value for the height. I entered a height of 14. The small box representing the induced air outlet needs to be vertically centered on the large box. You can use various tools to move it, including the MOVE command.
8. Select the small box, right-click and choose Move.
9. Pick the midpoint of the back vertical side of the small box.
   
10. Drag the cursor over the back endpoint of the 2D rectangle representing the small box and the midpoint of the vertical side of the large box to acquire these points. You don’t want to pick the points, you only want to pass over them so you can use Otracking (OTRACK must be enabled on the status bar). If you are not familiar with Otrack, these few steps are probably confusing… sorry…  This is easier to show than to explain. Viewing the animation will probably be very helpful for these particular steps.
11. Drag the cursor to the approximate location where you want to move the small box. You’ll know if AutoCAD acquired the points because the tracking vectors will display and the tool tip will indicate that it is tracking the Z values of the Endpoint and the Midpoint.
    

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Using these familiar tools (Osnaps. Otrack, MOVE, etc) you can easily manipulate objects in 3D space. We still need to make more changes to the VAV box. In the next posting, I’ll create the last two protrusions using slightly different methods.

Transitioning from 2D to 3D AutoCAD drawings 111

When I left off last week, I had 3D diffusers on the floor. Did you think about how I might move them to the ceiling?

As I mentioned in a previous post, there are many methods for selecting and moving the geometry in 3D space. I decided to use the Quick Select tool to select the objects and the standard MOVE command (rather than the 3DMOVE) to move the selected objects along the Z-axis.

1. In the drawing, right-click and choose Quick Select from the right-click menu.
   
2. In the Quick Select dialog box, set the Object Type to the type of object you want to move. Since I want to move blocks, I’ll set the Object Type to Block Reference.
3. Set the type of property for which you want to filter the selection. The property you choose depends on the drawing. In my example, I could filter on the block name. However, I have several different diffuser blocks so I would have to perform multiple sets of filters in order to select all of them. All of the diffuser blocks are on the same layer and they are the only blocks on that layer. So, in my example, the easiest method for selecting all the diffuser blocks is to filter on the layer.
4. Ensure the Operator is set to Equals.
5. Set the Value to the proper layer name. In my example, I set it to the M-HVAC-CDFF; the layer on which all my diffusers are inserted.
    
6. Choose OK. All block objects on the specified layer are selected and ready to be moved.
7. Right-click and choose Move.
8. Specify the basepoint by picking in a blank area in 3D space. This is no different than how you might move objects in a 2D drawing.
9. Ensure that polar tracking is enabled (POLAR toggle on the status bar). If polar tracking is enabled, you will see the Z tracking vector when you drag the cursor in the direction of the Z-axis.
10. Drag the cursor up along the Z-axis and enter the displacement distance. The displacement distance is 8’ in my example.
    

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Transitioning from 2D to 3D AutoCAD drawings 110

Now that we have lights… on the ceiling… let’s take a look at the diffusers. The diffusers are block insertions so I can update them quickly using the Refedit command, similar to how I updated the lighting fixture blocks.

The shape of the diffusers is a little more complex than the box-shaped lighting fixtures. That’s good! It gives me a chance to show you some other primitive tools!

The 2D block of the diffuser is flat and square. But, the real-life diffuser is a pyramid shape so I’m going to use the new Pyramid command in AutoCAD 2007. If you remember when I drew the box for the lighting fixture, it was like drawing a rectangle with height. Similarly, drawing a pyramid is like drawing a polygon with height. The first few prompts and options are just like the POLYGON command. To make the diffuser even more interesting and realistic, I’ll add a cylinder to the top face to represent the neck.

1. Zoom into a diffuser.
2. Select one of the block references, right-click and choose Edit Block In-place. This launches the REFEDIT command.
3. In the Reference Edit dialog box, choose OK.
4. From the Dashboard, select Pyramid.
   
5. Right-click and choose Sides.
6. Enter the number of sides for the pyramid. For this diffuser, I will enter 4.
7. Right-click and choose Edge. In this example, I could just as easily use the default Center option but I figured this way it is more obvious how the Pyramid options match the Polygon options.
8. With the endpoint object snap on, pick two endpoints on an edge of the existing 2D diffuser block. Now that I’ve defined the 2D shape (like a polygon), I am prompted for the 3D information.
   
9. Drag the cursor up and pick a point or enter a value for the height. I’ll enter a height of 1.25. The Pyramid is complete after entering the height. However, it used a default top-radius of zero, creating a point at the top. Before I entered the height, I could have right-clicked and selected the Top Radius option to make it flat on top. However, even after I create the Pyramid, I can edit its properties.
10. Select the Pyramid. I could enter a value for the top radius but I don't know what that value should be. Yes, I could figure it out using the DISTANCE command and snapping to the existing 2D geometry but I don’t want to work that hard! Instead, I’m going to use the Pyramid’s grips to snap to the existing geometry.
    
11. Select the grip for the top radius and stretch it out to the midpoint of the 2D geometry. In addition to grip-editing, you can use the Properties palette to modify the properties of a pyramid. You could, for example, change the number of sides, height, base radius, or top radius.
12. From the Dashboard, select Cylinder. Now I'm ready to create the neck of the diffuser.
13. Pass the cursor over the top face of the pyramid. The face should highlight indicating that it is the active workplane.
14. With the face highlighted, pass the cursor over the midpoints of two adjacent edges of the face. This will enable you to acquire the midpoints without actually picking. You must ensure that Osnap (with midpoint) and Otrack are toggled on. When AutoCAD acquires the points you will see yellow blips at the midpoints.
    
15. Pass the cursor toward the center of the face, until the tracking vectors is displayed indicating that it found the midpoint object snaps, and then pick. If these last few steps seem new, confusing, and overwhelming, they shouldn’t! This valuable 2D functionality has been around since AutoCAD 2000 and once you get familiar with how to use it, you’ll wonder how you worked without it.
    
16. Drag the cursor out and pick a point or enter a value for the radius of the cylinder. I want a radius of 3.
17. Drag the cursor up and pick a point or enter a value for the height of the cylinder. I’ll enter 1. But, again, I can change these values using grips or the Properties window.
18. Erase the 2D geometry to clean up the block.
    
19. On the Refedit toolbar, choose Save Reference Edits.  All of the block references for that particular type of diffuser will update with the new 3D geometry just as you would expect them to do when you make 2D edits to the block definition. I can repeat this process for similar block definitions of other diffusers.

Yeah!! We have diffusers! On the floor!

Think about how you might move the diffusers to the ceiling… or wait for a future post :-)

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Transitioning from 2D to 3D AutoCAD drawings - Dataset

I had a request to post the drawing files that I've been using for this series. So, here they are!

Download transitioning_from_2d_to_3d_drawings.zip

The ZIP file contains three drawings. The plan is the main file that I've been using. Don't forget to turn on your Dashboard for easy access to the named views, visual styles, and other 3D modeling tools!

The elevation drawing contains the cross sections for the beams. The model drawing is an example of how it might look after you've converted some of the 2D objects to 3D.

• Transitioning from 2d to 3d - 01Plan.dwg
• Transitioning from 2d to 3d - 02Elevation.dwg
• Transitioning from 2d to 3d - 03Model.dwg

Have fun!

Transitioning from 2D to 3D AutoCAD drawings 109

Okay… so you don’t want your light fixtures on the floor?!? 

There are many methods that enable you to change the position of objects in 3D space. Most of them are the same methods you use to change the position of objects in 2D! But, if you are new to working in a 3D environment, you might need to think a little more about which option to choose. For example, how should I select the orange light fixtures that I want to move? I could pick them one at a time but that sounds like a lot of work.

I could change to a plan view and then use several window/crossing selections just as I might do in 2D.

I could change to a front or side view and then use a window selection to choose just those objects (the light fixtures) that are at the floor level.

Or, the method that I’m going to use is the Properties window. Since all the objects that I want to select are blocks and because the light fixtures are the only visible blocks, I can select all the objects on my screen and then use the Properties window to select only the object type (Block references) that I want. This capability has been around since AutoCAD 2000 (if my memory servers) and it can be very useful whether you are working in 3D or 2D.

So why did I choose to use the Properties window for selection? Because, I can also use the Properties window to “move” my light fixtures to a new height.  Rather than using the MOVE or 3DMOVE commands, I can simply change the Z position of all the blocks to the proper value.

1. Select all the objects.
2. Right-click and choose Properties from the menu.
3. In the Properties window, select Block Reference from the drop-down list.
4. For the Z Position, enter the proper value. In my drawing, the bottoms of the light fixtures were originally inserted at a Z Position of 0 but I want them to be located at ceiling height which is 8’.
   

This method was the quickest in my situation because 1) it was easy for me to select all the right blocks and 2) I knew at what height (Z Position) the blocks should be. If I didn’t know the exact Z Position for the blocks, I would probably use a different selection method and then use the new 3DMOVE grip tool to move the blocks along the Z-axis at a relative distance (8').

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Transitioning from 2D to 3D AutoCAD drawings 108

In this series, I previously converted the structural elements and the walls from 2D to 3D objects. I turned off the structural elements (columns and beams) and turned on the lighting layer so that I can convert the 2D lighting fixtures to 3D.

Fortunately, my original 2D drawing included a reflected ceiling plan that used blocks to represent the various light fixtures. I can use what I already know about block editing to update the block definitions to 3D.  As I mentioned in a previous post, I can use various methods for editing the block definition; however, I suggest using the REFEDIT command. Once I’m in the reference edit mode, I can use any of my 3D tools to create the 3D model. I can use the PRESSPULL or EXTRUDE functionality that I described in previous posts or I can use primitive objects (BOX, SPHERE, CYLINDER, etc). I prefer to use primitive objects, when possible, because they have the most editing flexibility.

1. Zoom into a light fixture.
2. Select one of the block references, right-click and choose Edit Block In-place. This launches the REFEDIT command.
3. In the Reference Edit dialog box, choose OK.
4. From the Dashboard, select Box.
   
5. With the endpoint object snap on, pick opposite corners of the existing rectangle.
6. Drag the cursor up and pick a point or enter a value for the height. Even if you don't know the exact height, you can specify some value and then easily edit it later using grips or the properties palette. Keep in mind, however, that you must first access the block definition just as you would when editing 2D block geometry.
   
7. On the Refedit toolbar, choose Save Reference Edits.  All of the block references for that particular type of light fixture will update with the new 3D geometry just as you would expect them to do when you make 2D edits to the block definition.

I can repeat this procedure for the other light fixtures. Notice, however, that the light fixtures are on the floor. In a future post, I’ll show you one (of many) methods that will enable you to move them to the proper height.

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Transitioning from 2D to 3D AutoCAD drawings 107

When creating a 3D model, it can be useful to view it as a wireframe so that you can easily see and snap to points that might otherwise be obscured in a hidden or shaded view.

However, viewing your model as a wireframe can make it difficult to tell the top from the bottom or the front from the back. If you look at a wireframe model long enough you might convince yourself that it is upside-down or inside out.

For fun (because I’m sure you have tons of spare time), look at the images above and try to determine which side is up and then look at them a little longer and see if you can convince yourself of the opposite.

Now look at the exact same views with shading applied. This particular shading is using the Conceptual Visual Style.

Visual Styles are new in AutoCAD 2007. They replace the old Shade Modes that were available in previous releases but are considerably more powerful. Even if you aren’t ready to explore all the power of visual styles, I think you’ll find their most basic functionality useful to visually orient yourself within your 3D model. I use the Dashboard in AutoCAD 2007 to quickly switch between different visual styles as I’m creating my 3D model.

1. From the Dashboard, open the Visual Styles drop-down list. This displays image tiles that represent all the defined visual styles. AutoCAD 2007 includes 5 default visual styles: 2D Wireframe, 3D Hidden, 3D Wireframe, Conceptual, and Realistic.
2. Select the visual style you wish to use. I typically switch between the 3D Wireframe and the Conceptual visual styles but you might prefer to use others or to create your own. Continue to switch visual styles as often as necessary throughout the modeling process.

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Transitioning from 2D to 3D AutoCAD drawings 106

Continuing with my Transitioning from 2D to 3D series, I’ll finish creating the 3D walls using the 2D floor plan.

I could use the EXTRUDE command like I did for the interior walls in “Transitioning… 105” or I could use the PRESSPULL functionality like I did for the columns in “Transitioning … 102”. Given the choice of these two methods, I usually prefer to use the PRESSPULL functionality for two reasons. One, it doesn’t matter if the boundary is made of closed objects. The PRESSPULL functionality will produce a solid in either case. And two, I don’t have to launch a command. I can simply press the Ctrl-Alt key combination and pick inside the boundary. 

When using the PRESSPULL functionality, you must ensure that the entire bounded area is visible in the display. For example, the bounded area of the magenta lines (below) is completely visible on the display so if I use Ctrl-Alt and pick inside that area (the very small space between the parallel lines), AutoCAD can determine the boundary. However, if I use Ctrl-alt and pick inside the area between the parallel blue lines, that area is unbounded on my display (unless I zoom out) so AutoCAD will be unable to determine the boundary and the PRESSPULL operation will fail.

If you have a very large floor plan (or other bounded area), you might find it difficult to keep the full area within the display while still zooming in enough to pick inside the boundary. In some cases, it might be easiest to join all the segments to form a closed polyline and then use the EXTRUDE command rather than trying to use PRESSPULL.

In my case, the bounded area is just small enough to fit within the display and still enable me to pick within the walls.

1. Zoom, pan, and orbit so that the bounded area is completely visible AND there is enough room to pick inside of it.
2. Press Ctrl-Alt and pick inside the bounded area.
3. Drag the cursor in the direction you wish to extrude.
4. Enter the height of the extrusion or pick a point. You can use object grips or the Properties palette to change the height even after the solid is created.
   

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Transitioning from 2D to 3D AutoCAD drawings 105

Now that I have created the basic structural elements in this drawing, I’ll move on to the architectural objects. I want to create 3D walls from the 2D floor plan.

To make it easier for me to see the walls, I’ll turn off the structural layers.

There are several options for creating 3D objects for the walls. One method is to use the EXTRUDE command. The EXTRUDE command has been in AutoCAD since Release 12 but it has been enhanced in AutoCAD 2007. In previous releases there were different commands for surfaces and solids. If you wanted the walls to be surface objects you could use the TABSURF command but if you wanted them to be solid objects, you would use the EXTRUDE command. In AutoCAD 2007, you don’t have a different set of commands for surfaces versus solids. You can use the same command and, based on the initial geometry, AutoCAD will know whether to create a surface or solid.

If the initial geometry is an open object, such as an open polyline or an arc, AutoCAD will create a surface (left image). If the initial geometry is a closed object, such as a closed polyline or a circle, AutoCAD will create a solid (center image). Even if the initial geometry looks closed but is made from open objects, the EXTRUDE command will create surface objects. In the example on the right, the rectangle is really four individual line segments. Extruding those line segments produces four individual surface objects.

In my floor plan example, the interior walls are closed polylines so when I use the EXTRUDE command, AutoCAD automatically creates 3D solids for the walls.

1. From the Dashboard, choose Extrude.
2. Select the 2D objects you want to extrude.
3. Enter a height for the extrusion.
   

Even after you create extruded objects, you can use object grips or the Properties palette to change their height.

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By the way, if you are familiar with other architectural-specific applications such as Architectural Desktop or Revit Building, keep in mind that AutoCAD does not create real “walls” like those applications. AutoCAD creates 3D solids (or surfaces) that happen to look like walls. These objects don’t have any properties or data that are specific to walls. However, you could open this 3D AutoCAD drawing in an architectural application, such as Revit, and convert them to real wall objects.

Transitioning from 2D to 3D AutoCAD drawings 104

Continuing, again, with my “Transitioning from 2D to 3D” series, I’ll move the beams to the correct location (the ceiling instead of the floor!)

 

As always seems to be the case in AutoCAD, there are several ways to accomplish the same drawing task. I’m going to focus on what I think is the most intuitive method, enabling you to take advantage of what you already know from working with 2D drawings.

The first challenge with moving the beams in this particular drawing, is selecting them. There are several ways that you can select the beams. You could, of course, select each beam, one at a time, by picking them. Or, if you created all of the 3D Beams on their own layer, you could use the QSELECT command to select all objects on that particular layer. Another selection option, one that works particularly well in this case, is to change the viewpoint of the model so that you are looking at it more from an elevation view than from a top view. The Orbit functionality (Shift key and middle mouse button) enables you to transparently change the viewpoint of the model while you are in a command.

1. Begin the MOVE command.
2. Use the Shift key and middle mouse button to change the viewpoint.
3. Create a selection window that includes all the beams but does not include the columns.
   
   My selection window will include the single-line beams that I used for the sweep in my previous post. If I didn’t want those single-line beams to move, I could turn that particular layer off before starting the MOVE command.
4. Press enter to finish selecting objects.
5. Use the Shift key and middle mouse button to change the viewpoint so that it is more of a top view, making it easier to see the individual beams.
   
6. Use the middle mouse wheel to zoom into the end of one of the beams near a column.
7. For the basepoint of the MOVE command, select the midpoint of the top end of the beam.
8. Use the middle mouse wheel to zoom and pan to the top of the nearby column.
9. Ensure POLAR tracking is turned on (on the status bar) and the Midpoint object snap is enabled (Object Snap tab of the Drafting Settings dialog box).
10. Pass your cursor over the midpoint of the top edge of the column, which should be collinear with the midpoint of the beam.
11. Move your cursor so that polar tracking aligns along the Z-axis and the midpoint of the top of the column and then pick to place the objects. The tooltip will help assure that you’ve acquired the proper points.

Viola! The beams are now aligned with the top of the columns and I didn’t even have to type any values! Aside from using the orbit functionality to change the viewpoint, these are the same tools and methods (polar tracking and object snaps) that you use everyday (hopefully) when creating 2D drawings. Now you’re just applying those familiar tools to 3D space!

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Transitioning from 2D to 3D AutoCAD drawings 103

Continuing with my “Transitioning from 2D to 3D” series, I’ll use the existing single-line beams as paths for sweeping the beam profiles. The SWEEP command enables you to create a solid or surface by sweeping an open or closed planar curve (profile) along an open or closed 2D or 3D path. If you sweep an open curve, AutoCAD will create a surface. If you sweep a closed curve, AutoCAD will create a solid. Since beam profiles are not typically included in plan drawings, I copied them from the 2D Framing Elevation.  See Commandless Copy for more for information on coping objects between drawings.

The beam profile that I copied was a block. Before using the SWEEP command, I had to explode the block so I could access the closed polyline, which represents the cross-section of the beam.

From the Dashboard, choose Sweep to launch the SWEEP command.

1. Select the closed polyline, which represents the beam cross-section and then press enter to finish the selection set.
2. Select a line that represents a beam in the structural plan. AutoCAD automatically aligns the profile so that it is perpendicular to the path and it uses the centroid of the profile as the basepoint to follow the path. You can change the default behavior using the Alignment and Basepoint options from the right-click menu.
3. Repeat the SWEEP command using the same profile for each of the beam lines. Hint: Ensure that you have set AutoCAD to “Retain defining geometry”. See my previous post for more information.

The SWEEP command does not allow you to select multiple paths so you will have to perform this operation multiple times. However, you can use the AutoCAD API (Application Programing Interface) to automate the SWEEP command. Or, if the single line beams were inserted as blocks similar to the columns, you would only have to use the SWEEP command one time for each different block definition.

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Retaining defining geometry

Some of the 3D creation tools in AutoCAD 2007 use existing geometry to produce new 3D solids or surfaces. The default behavior in AutoCAD is to delete that defining geometry after the 3D operation has been completed. For example, if you sweep a profile along a path or revolve a profile around an axis, the original profile geometry will be deleted. In some cases, you may want to reuse that profile geometry for subsequent commands. If so, you can change AutoCAD’s default behavior so that it always retains the original geometry.

1. Right-click in the drawing window.
2. From the right-click menu, choose Options.
3. In the Options dialog box, choose the 3D Modeling tab.
4. Under “Deletion Control while creating 3D objects”, select “Retain Defining Geometry” from the drop-down list. You might find one of the other options even more approriate for your particular situation.
5. Choose OK to close the options dialog box.
   

Transitioning from 2D to 3D AutoCAD drawings 102

In my previous “Transitioning from 2D to 3D… 101” post, I provided an introduction to this series of posts in which I will show you how to update an existing 2D floor plan to a 3D AutoCAD model.

First, I’ll turn off some of the layers so that I can focus on the structural elements.

Then, holding down the Shift key and middle mouse button, I’ll move the mouse to change the viewpoint of the drawing. This means that I’m looking at the drawing at an angle rather than from directly above.

This drawing includes two different types of columns and therefore uses two different block references. Since the columns are block references, changes I make to the block definitions will automatically apply to all of the block references. This is typical AutoCAD behavior regardless if you are working with 2D or 3D geometry.

There are several ways to edit a block definition. In AutoCAD 2006 and 2007, you can use the BEDIT command to access the Block Editor. However, the Block Editor does not enable you to change the viewpoint of your block definition. You can use 3D creation tools in the Block Editor but since you can only view the geometry from the top, it might be difficult to see what you are doing. For this reason, I prefer to use the REFEDIT command. Using REFEDIT enables me to edit the block definition in the context of the rest of the drawing and it provides full access to the 3D creation as well as the 3D viewing tools.

1. Zoom into the column blocks.
2. Select one of the block references, right-click and choose Edit Block In-place. This launches the REFEDIT command.
3. In the Reference Edit dialog box, choose OK.
4. Press the Ctrl and Alt keys and pick inside the 2D column.
   The Ctrl Alt keys launch the Presspull functionality (you can also use the PRESSPULL command). As you pass your cursor inside the boundary of the column, AutoCAD detects the boundary and highlights it. You can then drag your cursor up or down to press or pull the 2D geometry into a 3D solid.
   
5. Drag the cursor up and pick a point or enter a value for the height. Even if you do not know the exact height, you can specify some value and then easily edit it later.
   
   AutoCAD creates a new 3D Solid object within the block definition. The new object is created on the current layer so you will want to be sure you have an appropriate layer set prior to using the Presspull functionality or change the layer property of the 3D object after it is created. The same layer rules apply to 3D as they do in 2D. For example, if you want block geometry to take on properties of the layer in which the block is inserted, you should create that geometry on layer 0 within the block definition.
6. On the Refedit toolbar, choose Save Reference Edits.
   All of the block references for that particular type of column will update with the new 3D geometry just as you would expect them to do when you make 2D edits to the block definition.
   

I can repeat a similar process for the other block definition. If I want the height of the second column to be the same as the first one, I can easily use what I know about object snaps in a 2D environment to quickly snap to the height (Z value) of the existing column. Although the new column appears to be too tall, as soon as I pick the endpoint of the existing column, AutoCAD will read the Z value and apply it to the new object.

               

Reading my explanation of this process takes a lot longer than actually performing these tasks in AutoCAD 2007. I can easily convert all the column blocks to 3D in less than a minute and a half!

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Transitioning from 2D to 3D AutoCAD drawings 101

During the Accelerate Your Ideas tour, I've been showing how AutoCAD can be used in different building environments to convert a typical 2D floor plan into a 3D model. Even if you have never created a 3D drawing, I think you’ll find that the new tools in AutoCAD make it an easy transition from your familiar 2D environment to the world of 3D. As you become more familiar and comfortable with the 3D conceptual design and visualization tools in AutoCAD, you may discover that you want even more power and flexibility. You can use the knowledge you’ve gained and the drawings you’ve created in AutoCAD to help you transition to Autodesk solutions that were specifically designed for the architectural, building structural, and building engineering industries.

During last week’s “Accelerate Your Ideas” tour, I learned a lot about how Autodesk’s building industry applications work together to provide a complete solution. If you are in the building industry, I encourage you to attend one of these valuable half-day events near you. The remaining cities on the tour include Boston, NYC, Houston, Atlanta, and Chicago.

www.autodesk.com/buildingevents

In the mean time I am going to begin a series of posts that step you through a process for converting a typical 2D AutoCAD floor plan into a 3D AutoCAD model. Even if you are not in the building industry, you can apply these AutoCAD tools and suggestions to typical drawings in any industry.

I'll begin with an AutoCAD drawing of a floor plan. This particular floor plan includes walls, basic structural elements, lights, diffusers, and ducts.

This is a typical 2D drawing. Actually, I should clarify… In reality, every AutoCAD drawing is 3D because every object has a Z value. However, in typical “2D” AutoCAD drawings, the Z value of all the objects is zero. You can view any AutoCAD drawing (in model space) from any viewpoint. However, in a typical 2D drawing, we always view the model from the top. If you change the viewpoint of a typical 2D drawing, you can see that it is flat.

The easiest way to change the viewpoint of a drawing in AutoCAD 2007 is to hold down the Shift key while you press the middle mouse button and move the mouse. There are many other ways to change the viewpoint in AutoCAD 2007 and earlier releases. For example, you can use the View command to set one of the predefined views such as Southwest Isometric.

As you change the viewpoint of your drawing, you may find that all the geometry is NOT flat. For example, if someone accidentally entered or changed the Z value of a block’s insertion point to a value other than zero, the block would be floating in 3D space. Working in a typical 2D view (looking at the drawing from the top), you might never notice the mistake, and it probably wouldn’t matter.

In the next post, I’ll show you how to update the existing 2D structural columns in the floor plan to 3D objects.

Quick Cubes!

When creating a 3D box or wedge in AutoCAD 2007, you can use the Cube option to quickly specify a shape with equal width, length, and height.

Start the BOX or WEDGE command and then specify the first corner of the base or use the Center option to specify the center of the object. When you are prompted to specify the other corner, right-click and choose Cube or type C. You can then specify a single distance and an angle to define the size and position of the box or wedge.

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Centering Boxes and Wedges!

In one of my previous posts, I described how AutoCAD primitive commands such as BOX and WEDGE enable you to easily transition from your familiar 2D world to the exciting world of 3D. With both of those commands, the default functionality feels like you’re drawing a rectangle… with height.

But wait! There’s more! Have you tried the Center option?

Immediately after you launch the BOX or WEDGE command (before picking any points), right-click and choose Center (or type C). The Center option enables you to draw the box or wedge based on the center point rather than a corner point of the base.

Tip: If you want to place the box or wedge exactly between two existing points, you can use the Mid Between 2 Points object snap by pressing Shift right-click and choosing it from the menu or by typing M2P.

The point you pick becomes the center for the base (length and width) as well as the height.

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AutoCAD 2007 Primitives: WEDGE

Think outside the BOX! Try a WEDGE!

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You can create a 3D solid wedge similar to creating a box. Begin by drawing a rectangle and then specify the height. However, keep in mind that when drawing a wedge, the first point you pick determines which side of the wedge will have height!

 

After you create the wedge, you can easily edit it using grips, similar to a box. You can edit the overall height of the wedge by stretching the top or bottom triangular grips and you can edit the width or length using the four triangular grips at the base of the wedge. The four square corner grips enable you to stretch the corners of the wedge to edit the length and width at the same time! You can use the square center grip to move the wedge without changing its shape!

In addition to editing the wedge with grips, you can use the Geometry pane of the Properties window to enter values for the length, width, and height of the wedge!

AutoCAD 2007 Primitives: BOX

Move to the 3rd dimension with AutoCAD 2007... it's easier than you might think!

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You can create a 3D solid box just like creating a 2D rectangle with height!

Even after you create the box, you can easily edit it using grips. The triangular grips enable you to stretch the box from any of its six sides and the square corner grips enable you to stretch the corners of the box to edit two sides at once! There is also a square center grip so you can easily move the box without changing its shape!

In addition to using grips to edit a box, you can edit its length, width, and height using the Geometry pane of the Properties window!