Release Notes-d2b

GroBoto UV Output Notes. 04.22.2011
UV Mapping in GroBoto
UV Mapping Options are
found in the Pop-Up
Menu in the lower-right
portion of GroBoto’s
Output Panel.
Left: Windows
Below: Mac OS X
There are four UV options:
1. Standard UV Map: Generates conventional unwrapping of the entire surface of the
Groboto model into a square in UV space.
2. Seam Profile UVs - Smooth: Maps only the ‘Seam Strip‘ — Intended for use with vertical
gradient images as a masking aid for modeling or painting in other 3D apps (see page 7).
3. Seam Profile UVs: Same as Seam Profile UVs Smooth - except that UV values are discreet
for each row in the Seam Strip.
4. None: No UVs generated or Output.
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GroBoto UV Output Notes. 04.22.2011
Standard UV Mapping in GroBoto
Here is a simple model —shown here as mesh preview
in Groboto — and it’s GroBoto UV map as seen in
Autodesk’s MudBox after OBJ Export & Import.
UV Map generation is fully automatic for meshes of
any complexity, all you need to do is hit the Export
button.
D
F
E
A
B
C
The portions of the mesh can be easily recognized (GroBoto Patches):
A & B: Top and bottom square caps of the button ellipsoid.
C: Lower part of the cylinder sidewall.
D: Upper cylinder sidewall.
E. Equatorial area of the button ellipsoid, punctured by the cylinder.
F. Inner parts and outer rings of the two cylinder caps.
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GroBoto UV Output Notes. 04.22.2011
Here's something a bit more complicated
... and its unwrapped mesh:
Each patch gets a separate piece of unwrapped mesh. A 'Patch' in Groboto is a contiguous piece
of surface bounded by seams (intersections with other surfaces), like the top of the nose as
shown here:
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GroBoto UV Output Notes. 04.22.2011
Some single patches unwrap into more than one piece (maximum three), depending on the
surface topology. For instance, a sphere cannot be unwrapped onto a plane in one piece
without producing ugly mesh distortion, but it unwraps nicely into three pieces, two squares on
the poles and one cylindrical piece that wraps around the equator:
So far we’ve looked at the GroBoto mapping produced when there is no Seam Smoothing in
effect. With Smoothing, mapping is essentially the same... just a bit more sophisticated.
Smoothing & UV Maps in GroBoto
With GroBoto Seam Smoothing active (as show in the Mac & Windows Output Panels below),
seams become significant elements of the mesh topology. Those elements are unwrapped
separately onto the UV plane.
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GroBoto UV Output Notes. 04.22.2011
Smoothing & UV Maps in GroBoto
With smoothing, the same model used in
the previous example (button ellipsoid
and cylinder), looks like this in GroBoto.
...and below, its UV map:
A
The UV Map is very similar to what we had
without smoothing, with one important difference.
Four horizontal strips [A] are added — each two
quads in height — corresponding to the seam
strips. On the left we see their location on the 3D
model (shown in Cinema 4D).
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GroBoto UV Output Notes. 04.22.2011
These strips are mapped separately because the surface they cover is deformed. It is no longer
the surface of the ellipsoid nor the cylinder. Those original surfaces have very nice UV mapping,
guaranteed to be free of ugly distortion, overlap, etc. However, attempting to extend that nice
UV mapping to the surface joining the cylinder & ellipsoid, would typically compress the UVs
and might even create overlaps. Separate UV mapping for seam strips is, on the other hand,
always distortion-free. Here, for instance, text placed over one of these strips (with any 2D
paint tool) maps beautifully with GroBoto’s UVs:
The large, sensible, UV patches created by GroBoto’s mapping are well suited for both direct 2D
painting and the 3D paint tools found in many 3D apps.
Exporting your GroBoto model to your 3D paint program with the Standard UV Map option
enabled is all that is required. Groboto maps every point on the model to a unique location in
that UV square, without distortion or overlaps.
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GroBoto UV Output Notes. 04.22.2011
Seam Profile UVs
Seam Profile UVs (called ‘Seam Masking UVs in earlier GroBoto versions), are handy as
modeling & painting masks in other 3D Apps — uses vary depending on the App. This option
produces no useful mapping outside of the Seam Strip. Mapping inside the Strip is onedimensional (only V values, U is constant map is read from a single column of the image).
Below is an example of a Seam Profile UV set up ZBrush. More examples can be found...
In Our Modeling Videos:
(Look for these thumbnails -->)
On the ZBrush Forum:
Many examples in this thread (starting
around page 13)
(Text version of links above)
http://www.zbrushcentral.com/showthread.php?t=61393&page=19&pp=15
http://www.groboto.com/v3/Documentation/TVideos/modelVid/
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