Manifold but self-intersecting printable?

I've been reading through the FAQ and tutorials, but haven't seen an answer to this. I thought I remembered reading about the topic at some point, but I'm not able to find it.

So, can you print an object that is manifold, but self-intersecting? To give an example: say I've modeled a hand. I decide that instead of individual fingers, I want the fingers together. Can I just move each finger so it overlaps the mesh of the finger next to it, or will having it intersect itself cause problems with the mesh?

Typically, I model hands with each finger separate and rig them so they can be posed, but if self-intersecting meshes are not allowed, then this would not be a good approach. I don't know of a tool to automatically "fix" self-intersecting meshes, so turning the individual fingers into a flat palm or fist would be very tedious modeling work.

Thanks for the info.

Yes, I model stuff that way all the time. As long as each piece of the mesh is manifold, it will work. Shapeways' software is smart enough to realize that the intersecting pieces should be joined.

Great news! Thanks for the response.

There's one pitfall that I've found whilst trying to get my Extruded Pipe D6 printable... when the curve is too tight for the diameter of the pipe/wire/finger, the sections overlap and this throws a non-manifold error.

That was my worry as well when I first came to Shapeways. However it is not an issue at all. I made my first 3d character from many pieces. His head, hands, forearms, upper arms, feet, lower legs, upper legs, head and chest are all separate pieces for easy posing within Sculptris not to mention his weapons and jewelry are multiple overlapping pieces as well. He is still a heavy WIP but I will be getting him printed as is in White Detail to see what details show up at 54mm. I'll post pics in It's Arrived someday...

One thing is, making complicated models like this have a very steep learning curve if you want a successful upload to Shapeways. You will need Netfabb for sure but there are tricks to using it. For instance running the default repair would always fix certain things but make the orientation hideously worse and non-fixable. So I found out there are certain things I should and shouldn't do, and also learned to go back into Sculptris, fix rough spots (one of his ears was too thin and a spot on his necklace on his back was heavily overlayed and needed to be ironed out. I have finally got it down to a science and am now able to upload any model I make with some tweaking. I should be gearing up for a heavy print order by Friday/Monday.




For more pics on the creation my thread on Zbrush Central:
http://www.zbrushcentral.com/showthread.php?p=732998#post732 998

Hi,

Our meshmedic will "merge/unify" intersecting pieces into one. This is for two reasons:
- easier for the printer
- more accurate volume calculation (volume is calculated per mesh, hence overlapping piece would be counted twice)

Kind regards, Arno