[Bf-committers] Sculpt Status - Week 3

Jason Wilkins jason.a.wilkins at gmail.com
Sat Jun 12 07:40:08 CEST 2010

== "On-Surface" Brush Cursor ==

The "On-Surface" brush cursor is drawn in a way that makes it appear to
follow the contours of the object being sculpted.  The brush tells an
artist precisely what areas will be effected by applying the current tool.
 Sometimes the area it highlights is quite convoluted and something the
artist never would have guessed from using the old cursor. Beyond that I am
experimenting with changing the brushes thickness, opacity, and color based
on different brush settings.  When using a pen, any changes to size or
strength because of pressure are also visualized as you go.

The brush is obviously very useful and I've received nothing but positive
feedback on it, however there is much work to be done before it can be
integrated into the Blender mainstream due to two reasons.  The first is
that although it can be implemented using standard OpenGL, for the triple
window update method it requires saving and restoring the depth buffer which
is an action that was overlooked in the original standard and is only
supported by a slow round trip to memory through ReadPixels/DrawPixels.
 Making it fast will require using two extensions ARB_depth_texture and
ARB_fragment_program (or any fragment shading extension that allows writing
The other reason is that the cursor requires the stencil buffer which is not
normally requested by Blender.

I believe that any reasonable target for doing digital sculpting in Blender
in 2010 supports all of these features because they have been a part of
standard mainstream OpenGL for years.  Stencil buffer was common even before
the release of Doom 3 which made extensive use of it.

Currently there are still some issues that need to be worked out but I
believe the special cursor is an important enough feature to justify
requesting the stencil buffer and using certain extensions.

== Locking Brush Size to Blender Units ==

I added an option to lock the current size of the brush relative to the
object.  This means if you zoom in or out that the brush will resize so that
it will be the same size relative to the object.
This allows an artist to work at different levels of zoom without having to
resize the brush in a time wasting attempt to match the size of the previous

== Texture Controls and Overlay ==

I improved the texture mapping controls, including a transparent overlay for
showing the orientation of the texture.  This is similar to mudbox and
zbrush "stencils"

== Grab ==

I improved the behavior of the grab brush.  The radius is doubled when
grabbing and moving the grabbed area around no longer causes it to become

More information about the Bf-committers mailing list