# 3D Modeling Special Interest Group – December 2017

In this session, we discussed the process for modeling a specific type of chair—a modern industrial X chair—and went through the construction step by step.

Topics covered:

• 00:17    We started off with the session discussing how to approach recreating a particular object, such as a chair. A chair can have many parts to it. The challenge is to break up the project into a series of manageable pieces. I always look for a hierarchy of parts and try to recreate them using the simplest methods possible. Can some be created by making simple extrusions? Can any be created by using the Extrude Along Path command? The remaining parts might be somewhat less straightforward and require more complicated techniques. We decided to start with the seat. When I’m faced with this sort of challenge, I center my object at (0,0) so that all the components can be placed mathematically in relation to the first component. Also, by setting the center of the object to (0,0), I can simply use the middle of the page as my center when mirroring parts of the object. The chair leg was pretty tricky because it was curving in two planes. We used the Extrude Along Path command to make it, rotated it in Top/Plan view, and trimmed off the excess. The back legs were less curvy and came up higher to support the back. We couldn’t just mirror the front legs for the back. The Snap to Tangent option came in handy, though we struggled to make it work for us. Finally, modeling that part in Screen Plane made the difference. A good test of whether the ends of your arcs and lines are touching properly is to use the Select Connected Objects command—if they are all highlighted, you know that they’re set up correctly. We trimmed off the bottom, rotated it and mirrored it to make our other back leg.
• 26:54    We wanted to make the backrest out of a Subdivision. It was going to be a challenge because it was flat in back, round in front, and curved from side to side. We started off with a cube and used various Subdivision tools to give the different surfaces curves or creases. We mirrored it so that any changes we made on one end would appear on the other. We added splits to the backrest, and gently curved them, one by one—that gave us the gentle curve we were looking for! Next, we needed to make the braces for the legs. Once again, we made our path and used the Extrude Along Path command. The Deform tool was useful for straightening the top of the front legs a bit, so that they weren’t so curvy. We continued by making the bracing for the front legs. The side bracing required a similar procedure. The X-shaped bracing along the back was trickier. First, we tried to use the Project tool and the Shell tool to get the shape. It didn’t quite give us what we wanted. Next, we just extruded a rectangle and bent it before mirroring it to make the criss-crossing braces. Selecting the whole thing, we added a cherry texture to our chair. In the end, it was a bit rough—but it was perfect for helping clients to visualize the concept!

3D Modeling December 2017 am

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