Fabric, Skin, Cloth expansion....best approach?

[Anonymous]

I'm trying to model an expandable metal frame (stent) that will have a layer of fabric and tissue sewn onto it similar to what is shown in the attached images. So far I've created the frame in 3ds, but I now need to add the fabric and tissue layers such that they will follow the expansion of the frame in my animation (see screen shot).

I'm wondering what the best approach is (cloth modifier, skin modifier skin wrap?). Not sure what the difference is between skin and skin wrap too. i have started to looked at the help topics for both cloth and skin and both seem to be pretty involved. Is there a simpler way to approach this? I would like to be able to create the fabric/tissue and then "tie" it to the frame at certain vertices and have it "follow" the expansion of the metal frame.

Any advice or direction would be greatly appreciated...

thanks
brent

[Anonymous]

I'm not sure how you went about animating the stent from the other thread, but if you used morph targets then it should be pretty easy to match up the tissue to the stent with another morph target system. This one should be easier since it's essentially a cylinder expanding out if I'm not mistaken.

About the cloth modifier, it's fairly hard to get the result you want without learning about it first and doing some practice. Even then, you might take a lot longer trying to get it to simulate how you want it and then adjusting vertices with a Edit Poly modifier.

The skin modifier is for using with a bone system like making a character, which I doubt you want to do.

The skin wrap modifier could give you some nice results as well because it will take your the tissue object and push it out based on the the stent's animation. The drawbacks I see while I was messing around with it is it has to calculate the movement of the stents vertices and then apply that to the tissue object's vertices or faces. I haven't used it a lot, but it seems like it might be similar to the cloth modifier where you have to play with the settings. You could also try making a lower poly dummy that follows the stent's movement for your expansion object.

I would go with morph targets first (if you can), and then skin wrap second. Morph targets give you the most control over your animation.

[Anonymous]

MK-3D - thanks for the suggestions. I did not end up animating the main frame with morphs... started to go that route but realized that i was going to be making adjustments vertex by vertex so I found easier to just use the Auto Key option and animate the vertices for each animation step as i went along. It made for a fair amount of Keys but it let me control the expansion very nicely so that it could coincide perfectly with the retraction of the sheath.

Based on that, I'm thinking I'll either do the fabric and tissue the same way, or give the Skin Wrap modifier a try... if I can get the fabric to match up to the control verts in the frame without too much trouble it might be the easiest way to go. Otherwise I'm looking at about 40 interim tweaks of verts to follow the frame expansion sequence with an Auto Key approach.

Thanks
B

[Anonymous]

If time is a factor, I would say go with whatever you think will be fastest. It might be faster to animate the vertices like you said, than to play around with the skin wrap modifier to get the results you want.

If you have time to learn about skin wrap, it couldn't really hurt and it will give you more knowledge. If you do play with skin wrap, I would make a lower poly object to use for the expansion object. Maybe copy your stent and put a optimize modifier on it, or animate a lower poly cylinder the same shape as your stent.

[Anonymous]

good idea - will play around with a simple cylinder poly and a plane with a bend first just to see if I can learn how to get the skin wrap modifier to give me the results i'm looking for. Not familiar with the Optimize modifier but I will check it out in the help topics (assuming it will automatically convert the complex frame into something much simpler)

[Anonymous]

Optimize is pretty simple. You just specify a threshold value and it will decrease the number of polys in your object. The higher the value, the more polys it will take away. It might not be great looking topology afterwards, but it will work for these purposes.