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Showing results for tags 'vellum constraints'.
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bentway23 posted a topic in EffectsI've probably overthought this and missed the obvious--I have multiple different groups of points (a changing number, this has to be scalable), and I want to create polylines between the border points--essentially connect adjacent pieces, but only pieces that are not in the current group, instead of only pieces that are. (The end result is creating prims to use as glue constraints in a grain setup connecting clusters of points. Because there are gaps between the chunks (and those gaps are where I want to form my polylines) using the connect adjacent pieces doesn't work because all adjacent points are found before the necessary distance has been covered. It's for a softbody tearing sim using grains for point deformation to compensate for vellum welds not accommodating solid objects--project file in this post: )
I'm building a relatively complex Vellum DOP setup using multiple objects with different constraint arrangements. The issue I'm having is my usual Achilles heel with this sort of thing: modifying attributes and values mid-sim. My specific issue is that I have a Vellum cloth object that is using the Pin to Target constraint option to follow some geometry I'm animating in SOPs. I created a point attribute for the target weights and that's working fine. My problem is that around halfway through the sim I want to animate down the target influence for this specific pin constraint. I have partially solved the problem using the Vellum Constraint Property DOP and animating the "Remove" value from 0 to 1 at the frame I want the pins to disengage. This works nicely as long as you're careful to select the specific constraint geo in the Group field of that DOP it will work. It's working so I'm going to get through this project using this method, but I'm having a really hard time figuring out how to modify my existing per-point constraint values using these fields. My questions: There are a bunch of specific vellum constraint attributes represented like Stiffness, Damping Ratio, etc. in the Vellum Constraint Property DOP that I can play with over time. Are these scalars that multiply by the point attributes I already have? Or are they values that will override the ones I've already set? Assuming they are overrides, is this why the VEXpression toggle and field is there? If I do something like "stiffness=stiffness*(fit($FF,50,100,0,1)" will this remember the original value of stiffness or is that being reset each frame? There is also the SOP solver methodology where I can modify the definition of the Constraint Geo over time. I can always fall back on that but it's also kind of tricky to setup. Hoping for something simple and effective that can just be wired into my DOP network. I really rely on the Sidefx example files to guide me through a lot of these setups, but I find that these kinds of constraint modification setups are in short supply. Would love to know how everyone handles this sort of thing. If anyone has guidance on this sort of thing, let's discuss. Thanks community.
Hi y'all, I wanted some advice on vellum balloons being attached to a string then popping (see reference below). So I can do the whole pressure thing and attach it to a string etc, but I wondered how to make the balloons automatically float upwards without just reversing the gravity. I don't want to just use a force to push them upwards, as it would look odd when they pop and don't fall to the floor. Any advice or example files would really be appreciated! Thanks, James