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.

1. 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.
2. Select the small box, right-click and choose Move.
3. Pick the midpoint of the back vertical side of the box.
   
   
4. Pass the cursor over the midpoint of the vertical side of the VAV box.
5. Move the cursor towards the intersection of the horizontal and vertical tracking vectors and pick.
   
   
6. Erase the 2D geometry.
7. 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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