GPv3: Sample Index node #114486

Dalai Felinto · 2023-11-04T16:52:04+01:00

Dalai Felinto commented

2023-11-04 16:52:04 +01:00

For this node to work for grease pencil, we force it to use the layer
zero. In the future we can add a Layer Index option, but for now this
will do.

This helps node-trees that were built for curves to also work for grease
pencil.

Part of #113602.

For this node to work for grease pencil, we force it to use the layer zero. In the future we can add a Layer Index option, but for now this will do. This helps node-trees that were built for curves to also work for grease pencil. Part of #113602.

Dalai Felinto added 1 commit 2023-11-04 16:52:14 +01:00

80ad14f2bc GPv3: Sample Index node

For this node to work for grease pencil, we force it to use the layer
zero. In the future we can add a Layer Index option, but for now this
will do.

This helps node-trees that were built for curves to also work for grease
pencil.

Part of #113602.

Dalai Felinto commented

2023-11-04 16:52:29 +01:00

My test file: greasepencil-nodes.blend

My test file: [greasepencil-nodes.blend](/attachments/4511a4f3-13fe-4387-803c-6da40dc09b82)

greasepencil-nodes.blend

155 KiB

Dalai Felinto requested review from Falk David 2023-11-04 16:52:48 +01:00

Dalai Felinto requested review from Hans Goudey 2023-11-04 16:52:48 +01:00

Dalai Felinto added this to the Grease Pencil project 2023-11-04 16:52:57 +01:00

Dalai Felinto removed this from the Grease Pencil project 2023-11-04 16:53:04 +01:00

Dalai Felinto added the

labels 2023-11-04 16:53:19 +01:00

Iliya Katushenock added this to the Nodes & Physics project 2023-11-04 16:59:31 +01:00

Falk David requested changes 2023-11-06 11:43:05 +01:00

Falk David left a comment

I don't think sampling from a grease pencil geometry by index will work in general.
Choosing the first layer is too arbitrary (and breaks when reordering layers). Allowing an index that spans across all layers is also too arbitrary imo. It also means that we don't represent the geometry well. The index essentailly looses all meaning. And combining all the layers into one big curves geometry has a big perforamance cost that we shouldn't do implicitly (users can still go for this approach if they merge all the layers manually into a curves geometry).

The only exception I can see is that we allow to sample by index if (and only if) the grease pencil geometry has a single layer. In this case, the sample by index is well defined.
The downside is that users might experience their setup breaking, just because they added a new layer.

I don't think sampling from a grease pencil geometry by index will work in general. Choosing the first layer is too arbitrary (and breaks when reordering layers). Allowing an index that spans across all layers is also too arbitrary imo. It also means that we don't represent the geometry well. The index essentailly looses all meaning. And combining all the layers into one big curves geometry has a big perforamance cost that we shouldn't do implicitly (users can still go for this approach if they merge all the layers manually into a curves geometry). The only exception I can see is that we allow to sample by index if (and only if) the grease pencil geometry has a single layer. In this case, the sample by index is well defined. The downside is that users might experience their setup breaking, just because they added a new layer.

👍 1

Dalai Felinto commented

2023-11-06 17:26:10 +01:00

@filedescriptor or we could implement the Layer (index) field input and use that to pick the layer? It is a bit strange to have a grease pencil only setting available when you working with meshes, but not sure how to solve that

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GPv3: Sample Index node #114486

Pull request closed