[Bf-committers] Clay Tool Bug

[Vox Lapin]

I definitely like the sound of that. I thought that the high "build-up" of
the clay brush was part of the design, but I would welcome access to a patch
to fix a bug and create a mode that does more "filling in" than "building
up". Could you post a link to the patch? I think the listserv eats
attachments.

On Wed, Jun 22, 2011 at 8:23 AM, Jason Wilkins <jason.a.wilkins at gmail.com>wrote:

> I ran into this while re-factoring sculpt.
>
> The clay tool in sculpt is supposed to obey the 'accumulate' flag.
> This flag tells sculpt if it should base the brush location on the
> original mesh before a stroke started (Accumulate Off) or use the new
> position of the mesh that it gets during the stroke (Accumulate On).
> Subjectively, accumulate 'off' looks like a brush has less and less
> effect as you use it on the same spot without starting a new stroke,
> sort of like how painting over the same area over and over doesn't
> change the color as much.  You can build up a sculpt in this mode if
> you release and restart your stroke in the same spot, but not if you
> just hold down the button and keep going over the same area.  With
> accumulate 'on' the sculpt will just build higher and higher without
> releasing the button but it is harder to get a smooth result.
>
> An option like 'Accumulate' is needed because unlike adding or
> blending a color, where it will eventually saturate to 1 or converge
> (respectively), a sculpting displacement can be applied indefinitely
> with continued effect.  Setting accumulate to 'off' lets sculpting
> simulate this saturation to some degree (could possibly be better),
> but it isn't obvious that this is always what should be done, because
> sculpting isn't painting.
>
> The bug is that clay is partially ignoring the Accumulate setting.
> When Accumulate is 'off' the brush location is correctly placed on the
> original mesh position, and the displacement vector is correctly
> determined from the original surface, however the amount that the clay
> brush raises the surface is computed from the new positions when it
> should come from the original positions.  The result is that even with
> Accumulate 'off', the brush still looks kind of like Accumulate is
> 'on', but because it is still using the original brush position and
> normals it simply isn't doing the right thing.
>
> I would just fix this, but I am unsure because somebody may really
> like how clay works now and by changing it to be 'correct' they will
> feel that I broke it.  However, I do think it should be fixed.  The
> old behavior can be mostly gotten back by turning 'Accumulate On' for
> clay, and it will accumulate correctly instead of in the potentially
> broken way it is now.  The subjective strength of clay with
> 'Accumulate Off' will seem weaker after this fix, but it will also be
> possible to get much smoother results because it won't build up on top
> of itself, allowing you to fill in gaps without applying too much
> clay.
>
> I've attached a patch, if anybody would like to test the difference
> just try un-patched and patched blender with accumulate turned on and
> off for the clay tool and tell me what you think.
>
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