Mark Christian

I have seen similar artefacts before - and recall eliminating them by fiddling with parameters in the subdivide node, and maybe the bevel node. I can't reproduce on your simple example. My hunch is your geometry is messed up with some duplicate geometry that sits on top of your intended geometry. You can't debug by eyeballing the geometry you need to upload your hip file.

I am not sure how you did things so I have done a couple of different approaches. It might help you track down your problem.

You need to change the attractor and node group nodes from “Primitive” to “Point” then the solver will work. Your difficulty here is the reason why I now will no longer buy Houdini training that does not include the .hip file, nor will attempt to rebuild .hip files for free tutorials (rather I will just sit back and watch!).

Houdini is a programming language it is very tedious and error prone to re write the program yourself as you listen and watch a video. If things go wrong you have to keep re-watching till you find what you missed. I checked the tutorial, and he does very clearly say change group type from prim to point in both cases - but it is so each to miss these key steps when you are listening / watching / build an node tree in another window!

Of course the fact that Houdini is a programming language means when tutorial authors give you the .hip file you can read the code and concentrate on understanding the algorithm rather than rebuilding. For me that is now the benchmark for handing over money - give me the .hip file!

I have been migrating a tutorial from Mantra to 3Delight. There is a limited number of 3Delight nodes you can use in a mat context. I was hoping you could mix houdini nodes with the 3Delight nodes: e.g. do some calculation to build say a value for the vector colour attribute, then convert the vector to 3 floats, the use the 3Delight FloatToColour node to build a 3Delight Colour object. The nodes join, types match i.e. the output of the Manta node is floats the input to the 3Delight node is floats, but the values get ignored.

It is not clear to me if this is because 3Delight is still Beta so not everything works as expected - or if by design this plugging of nodes is just never going to work? I would imagine the Houdini node interpreter would have no problem passing the float along so it must be 3Delight that is failing to get the plumbing to work.

The is a question in principle since I have worked around in 2 ways: 3Delight has a (horrible) condition node that can be used for the logic I needed (but doing so involves you implementing the logic 2x - once for Mantra once for 3Delight). My second solution was to take the nodes out of the mat context and put them in a VOP in the obj context and set an attribute. In the mat context you just then read the attribute using the supplied 3Delight node. This either means you end up with duplicate code in the obj context for 3Delight, and the mat context for Mantra, or you move shader logic out of mat context - which seems to be taking it away from where it should be.

I wanted to have a set up that had a switch to flick to move from Mantra to 3Delight and to share the Mantra logic as much as possible in the mat context.