2022-06-15 Geometry Nodes sub-module meeting

The meeting will be open for everybody interested in joining the video call (link below).

Meeting time: 15:00 CEST (Your local time: 2022-06-15T13:00:00Z).



General Discussion

  • Road to Siggraph 2022 - thoughts and initial planning
    • Artists at the studio are starting to be a bit excited to demo the new hair system at Siggraph. Dalai talked with Andy about what features would be useful to make the system exciting to demo.
    • Many of these are already being worked on by Jacques.
  • Hair Curve specific Geometry Node feedback
    • The most complex thing is probably the different hair types.
    • For example, creating a braid is basically impossible without hierarchical editing structures.
  • Hair Curve Sculpting Tools [feedback]
    • This post by Gareth (who was at the last meeting) expands on other tools that would be useful for the destructive pipeline as well.
  • Dalai has been working on the icons for brushes
    • What’s needed is a tool to make brush icons (images) from the Blender geometry tool icons.

Patch Review & Decision Time

  • D15188: Geometry Nodes: Add Message Node
    • This exposes something we can only do in builtin node
    • The fact that it uses the existing node warning system makes the implementation and design simpler.
    • The warning you create shouldn’t show in the header of the “Message” node itself.
    • One large complication is that it has to have an input and output in order to be evaluated (not optimized away by the evaluator).
      • It should support any type input (not just geometry sockets)
    • Dalai says that it looks a bit strange to have it look like a regular geometry node.
  • D15191: Spreadsheet: Support operations for filtering colors
    • The patch is straightforward, and can be committed
    • The color values for the spreadsheet should have soft limits [0, 1]
  • D15176: Geometry Node: Add: Material: Info, Count, Find, At Index, Copy, Clear Nodes
    • Exposing names has issues with dependencies, and is probably outside of the scope of geometry nodes as well.
    • Jacques mentions that the main issue with retrieving materials with indices only works when they are set manually directly.
      • This means that nodes like “Material by Index” don’t work well in a procedural context.
      • Another node could give a material output for a specific polygon (either selection or index input).
    • “Clear Materials” is redundant with the “Set Material” node with no material set
    • “Copy Materials” might be helpful in the future, but there also might be a more visual way to approach this.
    • Jacques mentions that there doesn’t seem to be a clear use case for the material count node
  • D15198: Geometry Nodes: Field to Mesh node
    • The functionality looks fantastic
    • There is some code review to do
    • There was some question about the word “Field” in the name
      • The final naming is a bit tricky
      • The node is a sort of primitive node, so a noun name might make sense
      • We discussed “Dense Volume Grid” and “Volume Grid”, and settled on the latter for now, since it was simpler and gives people fewer assumptions about what the node does
    • The design in T91668 is related. We want to add the ability to generate separate grids besides “density”. For now that’s okay though.
    • Density should be 1 by default
  • D12550: Geometry Nodes: Add Curve Curvature Node
    • Mainly this just needs some code review
    • The idea of outputting multiple related fields from the same input node made sense to everyone.

Help Needed

  • T95443: Refactor curve nodes to use new data structure is almost finished, but there are two more nodes that should be fairly separate that still need to be ported: the fillet curve node and the subdivide curve node.
    • Help in this area would be great, and there will be more to do when the basics of edit mode are working.
    • Hans mentioned that he would try to review the patch about the trim node this week.

Next Meeting

The next meeting will be on Wednesday 29 June, 15:00-16 CEST (Your local time: 2022-06-29T13:00:00Z), which is 2 weeks from this meeting. Again it will be open for everyone interested. The provisional meeting agenda will be linked in the #geometry-nodes channel before the meeting.