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Surgical Incision Animation


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Does anyone know or have done a surgical animation, particularly on circular path? I'm trying to figure out how I would go about animating the reference sample.

 

 

Any help would be amazing and look forward to anyone's suggestions. Thanks for taking a look!

 

-alemundo

 

Edited by Cerbera
Moved to correct section (see edit history)
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Well, thats disgusting 😉

 

But I would start with low-poly models for the skin, underlaying tissue, tools and hands. The movement of the tissue when it's touched I'd try with a collision deformer. For the actual cut you'll end up needing a copy of the tissue mesh that you slice manually (create edges and open the mesh at those edges). For the bending of the skin along the cut edges I'd put the low-poly skin mesh in a cloth object, give that one a little bit of thickness and put all of that in a subdiv object.

 

But thats all theoretical. I'd have to try different things along the way...

 

Edit: Didn't the collision deformer have something like "tear"? 

 

 

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Fantastic - thanks for the time, Kweso!

 

I follow everything you've mentioned, but the area I'm struggling with is how to open the mesh at the edges? I've figured out a way for a straight line, but not sure how to replicate for a circle path. 

 

I'm looking into the collision deformer as well - didn't think about that.

 

Thanks again!

alemundo

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I dont know if there is a "split (at) edge" command. What I would do is to use the poly pen (m-e) to draw my cut. Then select those edges along which I would want to make the cut. Then bevel the selected edges (without subdivision), select the polys that are created in between and delete them. Then switch to vertex mode, turn on vertex snap and manually move all the verices from one side onto the coresponding other...

 

maybe someone here has a better solution?

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What you can also do to get the cut edges is to draw a spline, then use the line cut tool, set your perspective and then ctrl-click the spline to project the spline as edges on your model...

 

 

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5 hours ago, kweso said:

I dont know if there is a "split (at) edge" command. What I would do is to use the poly pen (m-e) to draw my cut. Then select those edges along which I would want to make the cut. Then bevel the selected edges (without subdivision), select the polys that are created in between and delete them. Then switch to vertex mode, turn on vertex snap and manually move all the verices from one side onto the coresponding other...

 

maybe someone here has a better solution?

I feel the solution is in here somewhere, but man it's hard to follow. Do you think you can show me whenever you have a chance?

 

Thanks again, Kweso!

alemundo

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Poor Alemundo - I am also too busy to fully get into this right now - just bad timing I guess, but I do have time to pop in and say that we may be barking up the wrong tree here so far. I wouldn't worry about how to use splines to make cuts in objects. How to get the cuts in there is a relatively trivial matter, and the least of the issues we face here I'd say. By far the hardest part about this is making the bit you cut out seem invisible before it is cut. 

 

The collision and deformer stuff I don't have time to get into now, but I am aware that is a painful process to try and persuade any of Cinema's physical systems (soft bodies, cloth tearing etc) to try and fake this, so I think I would try with a pose morph based method where you start with 2 objects (the skin surface, and the round patch you will extract), which you model properly with the poly modelling tools so they match exactly. Now this is easy to make look seamless on a perfectly flat surface, but as soon as curvature and SDS starts getting involved then it will become painfully obvious that you start with 2 separate meshes. Unless you use a shrinkwrap deformer to fix that. Check out the below, where you can see you are looking at the 2 meshes, and despite being on a curved surface AND using live subdivision, they appear as 1 contiguous surface.

 

354628415_Invisblepatches.gif.fe8720813b09d43f703151db653aa19d.gif

 

This example obviously uses a perfect circle as the patch, but you can model in a more organic shape, and the technique will still work.

 

Then I think you need a pose morph (points) which would selectively draw the patch mesh inward following the path of a scalpel you pre-animated along it making the 'seen' cut. A further pose morph could work in conjunction with that on the outer mesh to make that draw away from the cut line also, hopefully giving the impression of a vaguely realistic skin cut.

 

I have yet to think this through further, or do the various tests necessary to see how exactly you could use that with your final models, but it is a place to start...

 

CBR

 

 

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