stbenge <THI### [at] hotmailcom> wrote:
> Here's what I did to get cube/height-field booleans to work in Blender:
>
> 1) added a mesh plane (the future height field)
> 2) added a subsurf modifier with the Simple Subdivision method, not
> Catmull-Clark
> 3) added a displace modifier
> 4) applied both modifiers to the plane, thus making the changes permanent
> 5) added and applied a decimate modifier to reduce the number of
> triangles in the plane, while trying to keep a good amount of detail
> 6) moved the object to another layer
> 7) added a cube to layer 1 and then added a boolean modifier pointing to
> the modified plane
> 8) applied the boolean to the cube (making it permanent) so Blender
> didn't take forever to recalculate it every time I tried to do something


That's one very useful insight: the idea of mesh plane (four points) and then
subsurf it until you get your image to show up as you like it. I was previously
adding a grid.  Decimation is in general a good practice, but for my scenario,
even a 0.78 decimation ruined the surface (caused me to lose features), so I
didn't apply.

After trying out your advice, however, I have to report that blender FAILS the
test. It cannot make both positive and negative surfaces that are cuttable.

BACKGROUND:  Suppose someone is going to insert carrot sticks vertically in an
array in ice, and then wants to be able to get cut-away views of the ice/carrot
arrangement.   The problem for this case is that you have to be able to take as
an input the position of the carrot sticks as a bitmap (white circles on dark
field).

Because of the way blender does booleans,  I am required to have both an "ice
w/holes" object and a "carrot stick assembly" object if I want to be able to go
back in and make cuts.

From a week of experimentation, and a morning of following your advice, making
one of those inexorably locks up blender.   :-(

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