Dynamic paint sub-steps don't work when the brush position is set in geometry nodes #98161

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Kevin Wright · 2022-05-16T13:03:17+02:00

Kevin Wright commented

2022-05-16 13:03:17 +02:00

I believe this may be the same issue as https://developer.blender.org/T40597

In order to have a brush follow a potentially very large collection of curves in sequence, I'm using geometry nodes to set the position, which avoids the pain of having to join the curve paths or painstakingly tweak the offsets and influence keyframes for each and every one.

This works, but with sub-steps enabled it seems that the nodes are still only being updated once/frame. Or, if they are being updated, then the seconds input from the Scene Time node is being derived from the frames value which is clamped to an integer.

text_path_test.blend

I believe this **may** be the same issue as https://developer.blender.org/T40597 In order to have a brush follow a potentially very large collection of curves in sequence, I'm using geometry nodes to set the position, which avoids the pain of having to join the curve paths or painstakingly tweak the offsets and influence keyframes for each and every one. This works, but with sub-steps enabled it seems that the nodes are still only being updated once/frame. Or, if they are being updated, then the `seconds` input from the `Scene Time` node is being derived from the `frames` value which is clamped to an integer. [text_path_test.blend](https://archive.blender.org/developer/F13078980/text_path_test.blend)

Kevin Wright commented

2022-05-16 13:03:17 +02:00

Added subscriber: @thecoda

Philipp Oeser commented

2022-05-16 15:43:53 +02:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2022-05-16 15:43:53 +02:00

Changed status from 'Needs Triage' to: 'Confirmed'

Philipp Oeser commented

2022-05-16 15:43:53 +02:00

Can confirm.

Philipp Oeser commented

2022-05-16 16:06:51 +02:00

Added subscribers: @JacquesLucke, @dr.sybren

Philipp Oeser commented

2022-05-16 16:06:51 +02:00

We are actually getting the right subframe in BKE_object_modifier_update_subframe, guess BKE_animsys_evaluate_animdata has some loose parts in concert with geonodes?

CC @dr.sybren
CC @JacquesLucke

We are actually getting the right subframe in `BKE_object_modifier_update_subframe`, guess `BKE_animsys_evaluate_animdata` has some loose parts in concert with geonodes? CC @dr.sybren CC @JacquesLucke

Jacques Lucke commented

2022-05-24 12:34:06 +02:00

BKE_object_modifier_update_subframe should really be end-of-live. It's honestly surprising that it still works in some cases with the new depsgraph...

I can kind of make it work for the specific case in the given file with this:

diff --git a/source/blender/blenkernel/intern/object.cc b/source/blender/blenkernel/intern/object.cc
index 2a25d73ed87..a66b5358f1a 100644
--- a/source/blender/blenkernel/intern/object.cc
+++ b/source/blender/blenkernel/intern/object.cc
@@ -4222,7 +4222,7 @@ void BKE_object_handle_update_ex(Depsgraph *depsgraph,
     BKE_object_where_is_calc_ex(depsgraph, scene, rbw, ob, nullptr);
   }
 
-  if (recalc_data) {
+  if (recalc_data || true) {
     BKE_object_handle_data_update(depsgraph, scene, ob);
   }
 }
diff --git a/source/blender/nodes/geometry/nodes/node_geo_input_scene_time.cc b/source/blender/nodes/geometry/nodes/node_geo_input_scene_time.cc
index 0222ccbbd02..86d82b8019f 100644
--- a/source/blender/nodes/geometry/nodes/node_geo_input_scene_time.cc
+++ b/source/blender/nodes/geometry/nodes/node_geo_input_scene_time.cc
@@ -16,7 +16,7 @@ static void node_declare(NodeDeclarationBuilder &b)
 
 static void node_exec(GeoNodeExecParams params)
 {
-  const Scene *scene = DEG_get_input_scene(params.depsgraph());
+  const Scene *scene = DEG_get_evaluated_scene(params.depsgraph());
   const float scene_ctime = BKE_scene_ctime_get(scene);
   const double frame_rate = (((double)scene->r.frs_sec) / (double)scene->r.frs_sec_base);
   params.set_output("Seconds", float(scene_ctime / frame_rate));

It's not quite clear to me why recalc_data is false when it should probably be true.

`BKE_object_modifier_update_subframe` should really be end-of-live. It's honestly surprising that it still works in some cases with the new depsgraph... I can kind of make it work for the specific case in the given file with this: ``` diff --git a/source/blender/blenkernel/intern/object.cc b/source/blender/blenkernel/intern/object.cc index 2a25d73ed87..a66b5358f1a 100644 --- a/source/blender/blenkernel/intern/object.cc +++ b/source/blender/blenkernel/intern/object.cc @@ -4222,7 +4222,7 @@ void BKE_object_handle_update_ex(Depsgraph *depsgraph, BKE_object_where_is_calc_ex(depsgraph, scene, rbw, ob, nullptr); } - if (recalc_data) { + if (recalc_data || true) { BKE_object_handle_data_update(depsgraph, scene, ob); } } diff --git a/source/blender/nodes/geometry/nodes/node_geo_input_scene_time.cc b/source/blender/nodes/geometry/nodes/node_geo_input_scene_time.cc index 0222ccbbd02..86d82b8019f 100644 --- a/source/blender/nodes/geometry/nodes/node_geo_input_scene_time.cc +++ b/source/blender/nodes/geometry/nodes/node_geo_input_scene_time.cc @@ -16,7 +16,7 @@ static void node_declare(NodeDeclarationBuilder &b) static void node_exec(GeoNodeExecParams params) { - const Scene *scene = DEG_get_input_scene(params.depsgraph()); + const Scene *scene = DEG_get_evaluated_scene(params.depsgraph()); const float scene_ctime = BKE_scene_ctime_get(scene); const double frame_rate = (((double)scene->r.frs_sec) / (double)scene->r.frs_sec_base); params.set_output("Seconds", float(scene_ctime / frame_rate)); ``` It's not quite clear to me why `recalc_data` is false when it should probably be true.

Kevin Wright commented

2022-05-28 01:13:43 +02:00

Okay, this sounds far more promising than I ever dared hope.

The diff to make it work could easily be scrawled on a postcard, and I've possibly surfaced a bug in recalc_data that might well be causing other problems. It also opens up other options in using geonodes to update positions and respect subframes for scenarios where drivers won't work.

Okay, this sounds far more promising than I ever dared hope. The diff to make it work could easily be scrawled on a postcard, and I've possibly surfaced a bug in `recalc_data` that might well be causing other problems. It also opens up other options in using geonodes to update positions and respect subframes for scenarios where drivers won't work.

Philipp Oeser removed the

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Dynamic paint sub-steps don't work when the brush position is set in geometry nodes #98161