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Showing results for tags 'houdini cloth fem best practices'.
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Afternoon all, I have to create a cloth sim, and my experience with cloth and FEM are lacking, as it seems are online resources (Last SideFX Masterclass was 2013), so I'm reaching out for any help you can offer. Hopefully this can be a good general tips resource beyond the documentation. Up shot is I'm being given a sculpted model that will I will have to fracture into organic patterns and simulate flying apart. Straight off the bat we've ran into some problems with the model and self intersections, and whilst this is an obvious issue with any model it's opened up the discussion on other things we should be considering at the modelling stage. For example topology - should we be trying to keep all edges the same length across the model? Does it not matter? Does it prefer quads? There are parts of the model that are best represented with the cloth closely doubling back on itself (like a hood edge) which seems to cause issues - Should we just be trying to represent what we can with single skin geometry and faking depth afterwards? Even if I take a known broken model and run a polydoctor on it to resolve intersections etc, I can still completely break the sim with crazy exploding (and I mean crazy, like pieces going out 1000000 units) - This made me think initially the resolution of the geometry was much too high, when in fact the only reason it was taking so long was having to resolve self intersection leading to mad explosion on the very first frame. Is there a rough poly/point count you will set as a rough limit? Any good guidance on limits for substeps or collision passes? Do you find yourself ending up at a similar sim time per frame for acceptable quality? (Pretty vague as it can change depending on the complexity of the sim but kinda links in with poly count etc). Posting your system spec would be helpful to give context to these answers. Any optimization tips here would be good too - For the tests I've been kicking off so far it hasn't looked like my CPU was being taxed too much, so I'm interested to know where the bottlenecks are and what to look out for. There are many options for collisions - Any you instinctively turn off to get up and running? I want to keep as many collision options on as possible but one (can't remember which, will update post when I'm back at work machine), was really murdering stability. Second point is pre-fracturing. I've been playing with sending fractures straight from a voronoi fracture (and the new edges it creates) compared to using it with an attrib transfer back onto the original topology and fracturing along existing edges. Haven't really decided which is best or if there is even any practical difference, so interested to know your thoughts. Most specifically with more organic patterns using the new boolean and cutting planes - Is there any reason this would be a bad idea if we're just fracturing surfaces rather than shapes? Is there a FEM cloth equivalent of for example bullet convex hulls? Or can we fracture until we're blue in the face? Thanks in advance for any help and information
