The Omnipotent 3D EXTRUDE Command


I love omnipotent, Swiss-Army knife, jack-of-all-trades type commands. ALIGN & EXTRUDE fit this category beautifully, and they’re both very useful in a 3D world. 20121010 1411 Extrude CaptureHere I will focus on the EXTRUDE command.

To whet your appetite for learning this command, let me just say that for many of you this will be about the one and only command that you will need to model over 99% of the objects you will ever want. If not, you will probably need to explore LOFT.

First, EXTRUDE allows you to turn a flat 2D shape such as a rectangle or circle into a 3D BOX or CYLINDER. The workflow is very straightforward: 1. Create a rectangle, circle or similar closed, but not self-intersecting 2D shape using PLINE or 3DPOLY. 2. Execute EXTRUDE command. 3. In response to “Select objects to extrude or [MOde]: ” prompt, select the 2D shape by clicking it, using the L(ast) object created option or your favorite entity selection method, then press space bar or enter to let AutoCAD know you’re done selecting objects. 4. In response to “Specify height of extrusion or [Direction/Path/Taper angle/Expression]: ” prompt, specify the distance for the height of the extrusion. You’re done. You’ve become a beginner 3D modeler. Here’s a video showing you how to do it:

Extrude Command’s Height Option

Theoretically, this is all you may need to model everything you’ll ever need. If you’re skeptical, think in terms of Finite Element Analysis (FEA) and FEAR not!

Secondly, you can use EXTRUDE to create not just a cylinder but also a CONE and even a simple hip and valley roof. What makes this possible is the Taper Angle option. Experimenting with this command earlier today in preparation for writing this message, I noticed some new interactive features that make AutoCAD feel like turbo charged Sketchup. More on this later as time permits.

Extrude Command’s Taper Angle Option

Thirdly, you can use EXTRUDE to create more complex shapes such as a sugar cane candy or stair handrail. You do this by taking advantage of the Path option. For the sugar can candy a 2D polyline will work fine. For a more complex shape that isn’t limited to a 2D plane, you must either use a 3D poly or break the operation into multiple parts that you can later join using the gluey, sticky UNION command.

Finally, as if this wasn’t enough, you can get more creative and use the EXTRUDE command to replace the DONUT, DOUGHNUT, TORUS, SPHERE and REVOLVE commands. Talk about Swiss-Army-knife-like ability!

This is certainly one of the commands I would want to have if I was to be limited to a certain number. I consider this command to be one of the Top 10 most important commands for 3D modeling.

You can certainly learn basic 3D modeling in about 90 minutes. Start learning 3D today. Ask if you get stuck. Remember: Ask and you shall receive an answer. If you have any questions about the EXTRUDE command, I’d like to hear and will love to answer them.

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Explore posts in the same categories: 3D BIM CAD, 3D Modeling, Basic Essential CAD, Education, Training, Uncategorized

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