MENOZ

because what applies to you doesn't necessarily apply to everyone else. If cops is enough for your work that's great, someone else might have different needs. (Rotoscoping, tracking, speed.. )

to get dark edges you need to use forward scatter in the shader and many bounces of light. even with 8 bounces you can see the effect of dark edges. the more the bounces the brighter it gets because it more likely that the ray bounces back into your eye. From what I can see the math is already there and working, but is a bit slow. Does redshift support multiple volume bounces? is it capable to simulate internal volume scattering?

Intersect VOP gives the coords on a surface, reading the help it seems to me more like dot(a,b)/length(b) https://en.wikipedia.org/wiki/Dot_product wiki calls it "Scalar projection" Never used softimage tho.

I would say is the laplace operator https://www.khanacademy.org/math/multivariable-calculus/multivariable-derivatives/laplacian/v/laplacian-intuition

have you unpacked the geo and converted to polygons?

have you checked the background value?

i think you SHOULD RFE to sidefx, they might come up with some clever idea to simplify or make it more accessible, you never know..

any luck with this?

i know about this university http://www3.math.tu-berlin.de/geometrie/Lehre/SS17/MathVis/

boolean is not doing that?

i would love that when you load an alembic file it put the point where the pivot was, not only on the centroid or at the origin

i tried this road but i'm stuck: i am trying to find the borders of the mesh with an attribute (I tried with the curvature and with another silly method, both gives the same results in this case) and primitiveSplit them so in my mind i would have the big face on one side, the faces at the borders, and the other side of the mesh. The problem is that this method is very dirty and i would need to create a clean seam line. Once you can separate the 2 big faces you can choose the one you prefer based on some parameters (like occlusion maybe?) and reproject it more or less in the position where the original scattered points were. The problem is to find a cleaner border edge to use to split the prims. maybe there is a good way to find the borders of the original scattered points, I usually count how many neighbours in a radius and use a treshold to filter those particles.. but is not always great, and use those border points to create a line, then extrude and boolean the mesh to split it. I attach the file if you want to have a look... :/ I'm pretty sure there must be some mathy way of finding those features. findBorders.hipnc

what's that? there are 2 nodes in cop to do vop operations, is this what you are looking for? http://www.sidefx.com/docs/houdini/nodes/cop2/vopcop2gen.html http://www.sidefx.com/docs/houdini/nodes/cop2/vopcop2filter.html you can do it easily with a couple of nodes, or i think there is a tool in the game shelf that is being developed, that does that. space + o toggles perspective and ortho

i don't think you can bend a ray in houdini, because i remember i've read somewhere that someone was trying to bend a refracted ray inside of an object of varying density, or something like that, and was not possible. I was doing tests ages ago to see if it was possible to control the direction of a ray passing through a volume, so sampling the volume in steps maybe and sending new rays.. but i've never got that far and i knew from the beginning it would have been super slow. what you can do is maybe using a lens shader, you can explicitly set the starting point and the direction of the ray for every pixel you want to sample. they will still be straight rays, but you can focus them where you need. I think this idea is what the mantra bake is doing under the hood: for every pixel set the position and direction of the camera and run throught the object. so you can maybe find the pos and dir in some way, even running a particle sim like StepbyStepVFX suggested,and using the last bits of the particles position and directions before they collide maybe. I can't remember how all of this plays with multisampling tho, i guess it just interpolate between positions in the sub pixels.

what do you have in mind?