anbt

I have selected the first points of some lines scattered around a tube like shape. I get what is on the image. I'd like to convert this into a polygon. You will tell me to just get the shape I used to scatter the line around, but to make it short, this is animated and the original tube shape doesn't move the same as the one you see in the picture (this comes out of a vellum solver) Hope I am clear. I could for example use a VDB from particles, but is there a node to just link all the points into a surface. A bit like a skin sop. Cheers

@Dweeble yes indeed, just once, and potentially later again at another frame. But I have no clue if this is gonna fix my problem, this is just an idea to try

Here is the full description of my issue with the hip file. I am generating a flip sim within a hollow VDB collider. That same VDB opens up at the top (ideally, I'd like the liquid to overflow from the top at some point), but for some unknown reason (possibly this VDB sign), the sim starts to get slow, and it stops filling up. https://www.sidefx.com/forum/topic/80058/?page=1#post-343937 I am baffled by this issue. And couldn't get any clue as to what's not working so far.

I am silly, I have to use a volume wrangle, but in the end, it doesn't do what I expected so whatever, this is not the way

Thanks for your answer, I tried but it doesn't change anything. Is my attribute wrangle placed correctly? I tried 'run over points' and primitive in the wrangle) Where can I see the sign value in the geometry spreadsheet of my static object VDB collider, so I can see if anything changes? Cheers

thanks again for this @ibamobt. your 2nd method produces an interesting result but the VDB is made out of particles, so it gets full of holes as it grows! But it looks rad! In your first method, you polyfill the shape, so it's closed, and it works. I forgot to mention that instead of having a closed shape, I want to thicken it so it stays open at the top, but the VDB would work because it is extruded/thickened. I am trying to fill this shape with liquid as it grows. But I am encountering a problem at a certain frame. It stops filling and gets extremely slow. I think this is because the VDB is starting as a closed and hollow shape with the liquid generated inside, then it opens up at the top, and it starts getting weird. I have no idea how to fix this, perhaps I should invert the VDB sign at this specific frame, I don't know, it is a bit beyond me. I also have to thicken as hell my VDB collision geometry, and it doesn't match my initial geo anymore, that sucks, and couldn't find another way around this! If you have some knowledge in flip sim or anyone else can help, that would be awesome. I have attached the hip file Thanks! test_liquid_inside_vdb.hip

Oh thank you very much, I will look at this as soon as I can!

@ibamobt here you go, thanks for having a look vdb_issue.hip

fixed it by inadvertently adjusting the mass of these constraints points! Not sure to understand why this works because I would have thought the stiffness matters here

I am really puzzled by this. It is a regular flag setup, with the top edge points attached to the collision geometry with some attach to geometry constraints. Whenever my collision geometry moves quickly, the constraints gets stretched even when I set them to be really stiff. Any idea? Thank you

I tried with a volume wrangle and multiply by -1 the name of my volume (collision), it didn't work if ($F>178) { @collision *= -1; } Any idea? Thank you

so now, I fixed one problem, but I get a new one in return for free I made my collision volume way thicker, which I didn't want to because I can't get a nice liquid filling closely along the inside surface but at least, it fills up the inside until a certain frame, and then, it suddenly stops. I noticed by visualising collisions in the flip object (the stuff in purple) that my collision area reverses itself at a specific time (it kind of inverts the sign of the SDF. I mean not kinda, this is what happens!) I figured out it comes from my shape which starts as a closed shape (a hollow shape but closed), and then it opens from the top. And it is at that specific moment my liquid starts to act weird. It doesn't fill, and it gets extremely slow. Any idea how to fix this? So far, I managed to fix everything but now, it starts to get too tricky and I am sure the answer will be a line of Vex to tell my volume to not inverse itself at the specific frame but I don't know how to do this. Or is it something else? Cheers!!

Hello guys, I am desperate on this one! I want to fill with water this evolving shape that starts from nothing and expand like a flower. The idea is to make the fluid squirt out of it from the top (there is a hole on the top of the geo) but to start, I was thinking of filling the geo first. Maybe there are other ways to get the squirt going but I would like to fill the shape with liquid first. I am aware that I should use deforming VDB object for collision, I know the workflow but there is definitely something I don't know here. Whatever I do, the liquid goes through. I tried with a super high res VDB or even 8 substeps, nothing works. I suppose it will be easier if I attach the file so here it is test_ffluid_inside_growing_geo.hip Any idea? Thank you very much

Hi there, As you can see on the video attached, my VDB is jumping from being fine to suddenly being almost gone, and then appearing again. What could be happening? The geometry that has been turned into a VDB has a fixed number of points. It was a curve fed into a revolveSOP, curve has been resampled to a fixed number and then that curve is scaled. Thats why the number of points is not changing. I am mentioning this because maybe it matters, but it probably doesn't. I don't know! If anyone knows how to fix this, that would be awesome!!! Thanks 2021-07-08 17-06-31.mkv2021-07-08 17-06-31.mkv

maybe I could turn those plants into a really stiff vellum and the collisions would be handled there, but with all the remeshing needed to get the geometry to work with vellum, I am not sure I would end up with a satisfying result. And it might be super slow if I instance thousands of plants!!!