Fix for wobbly volume object outlines in the viewport #111657

Lukas Tönne · 2023-08-29T15:57:14+02:00

Lukas Tönne commented

2023-08-29 15:57:14 +02:00

The outlines of volume grids in the viewport are noticeable "wobbly"
when they should simply represent grid boxes. This is especially
noticeable on simple regular grids such as the "Volume Cube" geometry
node output.

The reason is that the outlines generated by taking a triangulated mesh
of the grid boxes and then growing it by successively scaling each
triangle. The offset for each vertex grows proportional to its degree
(number of connected edges). The fix is to divide each vertex's offset
by its degree.

The resulting mesh is much more regular and closer to to 1% desired
growth factor.

Old:
New:

The outlines of volume grids in the viewport are noticeable "wobbly" when they should simply represent grid boxes. This is especially noticeable on simple regular grids such as the "Volume Cube" geometry node output. The reason is that the outlines generated by taking a triangulated mesh of the grid boxes and then growing it by successively scaling each triangle. The offset for each vertex grows proportional to its degree (number of connected edges). The fix is to divide each vertex's offset by its degree. The resulting mesh is much more regular and closer to to 1% desired growth factor. Old: ![Screenshot_20230829_155602](/attachments/87fbdca3-fb9d-49d8-b4f5-6780d1c72f79) New: ![Screenshot_20230829_155648](/attachments/4452c52b-96df-4200-a02f-3d0d8aa8680e)

Screenshot_20230829_155602.png

135 KiB

Screenshot_20230829_155648.png

143 KiB

👍 1

Lukas Tönne added 1 commit 2023-08-29 15:57:24 +02:00

ca55e85ed2 Fix for wobbly volume object outlines in the viewport.

The outlines of volume grids in the viewport are noticeable "wobbly"
when they should simply represent grid boxes. This is especially
noticeable on simple regular grids such as the "Volume Cube" geometry
node output.

The reason is that the outlines generated by taking a triangulated mesh
of the grid boxes and then growing it by successively scaling each
triangle. The offset for each vertex grows proportional to its degree
(number of connected edges). The fix is to divide each vertex's offset
by its degree.

The resulting mesh is much more regular and closer to to 1% desired
growth factor.

Lukas Tönne added this to the Nodes & Physics project 2023-08-29 16:02:29 +02:00

Lukas Tönne commented

2023-08-29 16:06:12 +02:00

Some mathematical reasoning: Growing the surface by 1% does not directly lead to concrete vertex offsets, it requires solving a large equation system.

The current algorithm tries to arrive at a solution by solving each triangle in turn and adding up the solutions, which does not quite work. By simply dividing the sum by the number of vertex edges this can be turned into a proper Jacobi solver. It's still a single iteration but for the purpose is good enough.

Some mathematical reasoning: Growing the surface by 1% does not directly lead to concrete vertex offsets, it requires solving a large equation system. The current algorithm tries to arrive at a solution by solving each triangle in turn and adding up the solutions, which does not quite work. By simply dividing the sum by the number of vertex edges this can be turned into a proper Jacobi solver. It's still a single iteration but for the purpose is good enough.

Lukas Tönne requested review from Jacques Lucke 2023-10-06 15:14:06 +02:00

Lukas Tönne added 1 commit 2023-10-06 15:16:02 +02:00

8d0a6fb081 Merge branch 'main' into fix_wobbly_volume_outline

Jacques Lucke approved these changes 2023-10-06 16:58:05 +02:00

Lukas Tönne merged commit 711c9c5553 into main

2023-10-06 17:43:14 +02:00

Lukas Tönne referenced this issue from a commit

2023-10-06 17:43:15 +02:00

Fix for wobbly volume object outlines in the viewport

Lukas Tönne deleted branch fix_wobbly_volume_outline

2023-10-06 17:43:16 +02:00

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Fix for wobbly volume object outlines in the viewport #111657