2021-12-6 - 2021-12-10 Geometry Nodes Sub-Module Meetings

Info

Developers or artists interested in contributing are welcome to join at the links below.

Week of 2021-12-06

  • T93817: Convert Triangulate node input to a selection
    • With recent input node additions, the minimum vertices can be built from simpler parts.
    • The idea looks like a straightforward improvement
    • Could we used Mesh-based triangulation instead of converting to BMesh? Maybe.
  • Showing 3.1 targets to Simon and Dalai.
    • Hans is probably not available (traveling in the morning).
  • T93834: Customize normal of first control point in minimum twist mode
    • The up vector could be stored as a spline domain attribute and used for the “start vector” of the minimum twist mode
    • Store an up vector on every spline OR on every point
      • The up vector is used as the initial vector at the start point for the minimum twist normal mode.
      • The up vector can also be constant, e.g. for (0,0,1) it would have the same results as the Z-up mode.
      • This is better defined than storing the a custom normal directly, because it’s still valid after transforming/rotating the spline.
      • This could be a reserved name attribute or a built-in attribute.
        • Benefits of reserved name: It can exist conceptually on multiple domains
        • Benefits of built-in: The 3D vector data type is guaranteed
      • The attribute name could be normal_up_vector (can be changed later)
      • The tilt would still apply on top of the calculated normals.
    • Another option was storing a custom normal per point (had more downsides than the up vector option):
      • There could be a custom normal layer on curve control points.
        • A vector stored on each control point that could be used in nodes like curve to mesh instead of the derived normals.
        • It would have to be a built-in, because they need to be normalized and orthogonal to the tangent
          • The could be normalized and made orthogonal on demand, but that would be harder to debug, since the data used would be different than the data you see.
        • Possibly the same name used for meshes, custom_normal
      • The other normal mode is “Z up”. Theoretically that could be implemented with the same “custom normal” idea.
  • Node link search feedback from Simon
    • Esc should work to cancel dragging.
    • Add entry with just the node name with default behavior, in addition to their sockets.
    • Add shortcut to open the search directly.
      • Shift S
        • Used by switch node operation by node wrangler. Can it be changed.
    • Drag + key press to quickly add commonly used nodes.
    • In the future, check the output geometry type of nodes and only show connections when they make sense.
  • Named attribute discussion
    • Another related thing is default names for field inputs on the modifier
    • Could that be generalized for all group inputs?
    • You should always be able to see what external data (named attributes) a modifier depends on, and change it.
  • Group Defaults
    • A way to let node groups define default inputs that are used when nothing else is connected.
  • Node group asset preview generation
    • Options:
      • Render of the active object
      • Mini-map-like view of the inside of the node group
      • Screenshot of the outside of the node group
    • Simon: Screenshot of the outside of the node group is probably the best first option.
    • Make adding a custom preview very easy
      • Add an operator that lets you screenshot an arbitrary rectangle and make it a preview
14 Likes