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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