Use Scene Spacing Distance by default #99609

New Issue

Julien Kaspar · 2022-07-11T14:26:44+02:00

Julien Kaspar commented

2022-07-11 14:26:44 +02:00

NOTE: This design is still being investigated and discussed.

Issue

The default for brushes in every mode has always been to use view based spacing for each stroke.
This wasn't always an issue since brushes used to work via a projected falloff.

But when using a spherical falloff on curved surfaces this can lead to inconsistent spacing artefacts.
Since more painting and sculpting modes are implementing brushes with a spherical falloff by default, it is a reasonable adjustment to make the spacing also scene based.

First Steps

Before changing any defaults we should investigate any remaining issues, downsides or bugs if this behaviour would be implemented by default for all brushes.
Once it is clear that this change would be an overall improvement, and how feature might need to change.

Fix remaining bugs and issues

Further issues from using Scene Spacing need to be investigated.
The currently known reports are:

#98111 (Sculpt mode: Draw Sharp brush artefacts when using Scene Spacing in stroke settings)
#99638 (Line stroke method not working with Scene spacing)
#99642 (Clay strips brush freeze when coming from outside the horizon of surface curvature)
#99644 (Draw Sharp brush stops on anchored during the stroke)

Proposal

Scene spacing currently accomplishes two distinct behaviours:

The spacing is consistent in 3 dimensions
The spacing is consistent in world space (especially when zooming in/out)

Instead of just making Scene Spacing Distance the default, we should change the "View" scene spacing to work 3 dimensionally for a better brush behaviour in general.
This could be accomplished by associating these two different behaviours with distinct settings:

Setting the falloff to be Spherical or Projected = 3D or projected spacing distance
Switching between View & Scene spacing distance = The spacing is a percentage of the relative brush size diameter or an absolute world size

The UI should then also reflect that change, by changing the spacing slider value:

View = Percentage
Scene = Distance in units

This updated View spacing then needs to be integrated in every mode for 3D painting/sculpting.

NOTE: This design is still being investigated and discussed. # Issue The default for brushes in every mode has always been to use view based spacing for each stroke. This wasn't always an issue since brushes used to work via a projected falloff. But when using a spherical falloff on curved surfaces this can lead to inconsistent spacing artefacts. Since more painting and sculpting modes are implementing brushes with a spherical falloff by default, it is a reasonable adjustment to make the spacing also scene based. # First Steps Before changing any defaults we should investigate any remaining issues, downsides or bugs if this behaviour would be implemented by default for all brushes. Once it is clear that this change would be an overall improvement, and how feature might need to change. ### Fix remaining bugs and issues Further issues from using Scene Spacing need to be investigated. The currently known reports are: - #98111 (Sculpt mode: Draw Sharp brush artefacts when using Scene Spacing in stroke settings) - #99638 (Line stroke method not working with Scene spacing) - #99642 (Clay strips brush freeze when coming from outside the horizon of surface curvature) - #99644 (Draw Sharp brush stops on anchored during the stroke) # Proposal Scene spacing currently accomplishes two distinct behaviours: 1. The spacing is consistent in 3 dimensions 2. The spacing is consistent in world space (especially when zooming in/out) Instead of just making Scene Spacing Distance the default, we should change the "View" scene spacing to work 3 dimensionally for a better brush behaviour in general. This could be accomplished by associating these two different behaviours with distinct settings: 1. Setting the falloff to be Spherical or Projected = 3D or projected spacing distance 2. Switching between View & Scene spacing distance = The spacing is a percentage of the relative brush size diameter or an absolute world size The UI should then also reflect that change, by changing the spacing slider value: - View = Percentage - Scene = Distance in units This updated View spacing then needs to be integrated in every mode for 3D painting/sculpting.

Julien Kaspar commented

2022-07-11 14:26:44 +02:00

Added subscribers: @JulienKaspar, @JosephEagar

Julien Kaspar commented

2022-07-12 15:59:03 +02:00

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

Julien Kaspar commented

2022-07-14 12:10:11 +02:00

From the recent module meeting:

A possible improvement to investigate further.
Julien will test the behaviour to try to find more issues.
Joe wants to look into one fix: Increase the minimum allowed spacing of stroke points with scene spacing. This could already improve performance.

From the recent module meeting: > A possible improvement to investigate further. >Julien will test the behaviour to try to find more issues. > Joe wants to look into one fix: Increase the minimum allowed spacing of stroke points with scene spacing. This could already improve performance.

Julien Kaspar commented

2022-07-14 18:39:19 +02:00

Another big issue with scene spacing distance that would be worth investigating:
Depending on the world space dimensions of the object the brushes will behave very differently, because the brushes take absolute world space for the distance.
So brushes might work on a regular scale of 1 blender unit, but will use completely different spacing when sculpting micro details on a finger or broad shapes of a Kaiju ...

We might want to look into a solution. Because one important feature of scene spacing is not that it takes the absolute world scale into account, but that the spacing is working in 3 dimensions instead of being projected from the view.

That is something different from using Scene spacing to keep the spacing consistent when zooming in & out.

EDIT: I updated the description based on this.

Another big issue with scene spacing distance that would be worth investigating: Depending on the world space dimensions of the object the brushes will behave very differently, because the brushes take absolute world space for the distance. So brushes might work on a regular scale of 1 blender unit, but will use completely different spacing when sculpting micro details on a finger or broad shapes of a Kaiju ... We might want to look into a solution. Because one important feature of scene spacing is not that it takes the absolute world scale into account, but that the spacing is working in 3 dimensions instead of being projected from the view. That is something different from using Scene spacing to keep the spacing consistent when zooming in & out. EDIT: I updated the description based on this.

Julien Kaspar commented

2022-07-18 10:45:54 +02:00

To fix the issues properly and improve stroke behaviour @JosephEagar created #99784

Julien Kaspar added this to the Sculpt, Paint & Texture project 2023-02-08 10:20:48 +01:00

Philipp Oeser removed the

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Use Scene Spacing Distance by default #99609

Issue

First Steps

Fix remaining bugs and issues

Proposal