Friday, August 24, 2012

Building a better dragonfly

After finding the worst possible way to get my dragonfly body from Sculptris to Autodesk Inventor,  and then finding a slightly better way. Inventor was still choking on the geometry. It could handle it, and it looked decent, but it was still causing performance issues on my weak sputtering old pc. I learned that if I made nurbs in 3ds Max. I could export them as an IGES file and inventor would take them in as if they were their own. It would love them and hold them and happily stitch them to a solid with no resistance, no long waits, no CPU spike, no whirring chewbacca fans blowing smoke out the back of my tower.
 The file size is only 200k, rather than the whopping 30-40mb of the previous methods..

Here's what it looks like now.

I first learned that exporting IGES files would preserve the smooth surfaces from inventor and import them into 3DS Max as solid bodies. So, I wagered that the opposite might be true as well. I decided to try it out, and it worked perfectly. With a small win under my belt, I set to find a way to salvage what I already had made in Sculptris. I made some attempts to find a free program that would convert the geometry to a nurbs surface and save it as an IGES. However I kept finding the same answers over and over. 100s of posts in dozens of forums, and the same advertisers saying... "Our product can do that! Come buy it!".
No free lunch today it would seem. Coincidentally, I skipped lunch today so I could write this.

With no free lunch, and nothing to make my sculpted body play nice with inventor. I decided, to scrap it. I started a brand new body made from actual nurbs inside 3ds Max. It wasn't as easy as sculpting. But, it wasn't horribly painful either. All in all, it wasn't a bad first experience in 3ds Max. The only down side I could see was that the nurb editor felt a lot like a plugin. Something that got tacked on afterwards.
That lead me to believe that maybe there was something else I should be using. So, I did a little digging again, and it was looking like Rhino or Maya were the nurb editors of choice. But, nothing free. Except blender. Once again I hear the murmers of the web telling me "blender can do that".

Now that the body is finally finished I can perhaps get onto wrapping up the wings, and the project in general. Here's a video of the project in its current state.

Everything is complete now except the wings.
They look a bit too much like butterfly wings, and not like dragonfly wings. I'd like to fix that.

Standard issue poly/quad meshes like the ones made in sculptris are perfectly good and are a more than acceptable method of producing geometry for 3D printing. But, unfortunately Inventor seems to hate them. Inventor specializes in designing "feature driven" models. Cutting and welding and folding, hole making, etc. So, when it comes to designing moving parts within the tolerances set forth in shapeways design guidelines I feel very comfortable in Inventor. But, for the organic stuff, it's less than ideal. If you plan on importing something into an inventor project that is organic in nature. It looks like designing it with nurbs and exporting as an IGES file is the best way to go.

Thanks for reading!

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