Fix the UV map

abstract:In this tutorial I will show how you can examine your UV-map and how you can recover your sculptie. The tutorial was made with Jass-magic. But it is also valid for all other jass-products and primstar-1.1. Some details vary however (The sculptie previewer is only available in Jass-Magic).

intended audience:

  • Creators of “sculpted prims” for OpenSim and similar environments
  • Blender novice (low/mid level skills)

prerequisites (*):

  • download: jass-2 (binary distribution, contains blender-2.49b, python-2.6.4, primstar-1.0.0 and more)

related tutorials:

Separate Downloads:

(*) If Jass-2 is not an option for you, you can download the prerequisites separately:

  • download: blender (2.46 or newer, 2.49b recommended)
  • download: python (2.6.4 for Windows, 2.5.2 for Mac OS)
  • download: primstar (1.0.0 or newer) by Domino Designs or alternatively get your free download link for primstar-1.1 from our Jass-Shop
Transcript
Hello and welcome!
This sculptie is apparently based on a torus shape.
Let us examine the stitching of this object.
  • Go to edit mode
  • and in the UV-editor ensure that you have enabled “Sync UV and mesh-selection”.

Now you can select vertices in the UV-editor and immediately see the corresponding
vertices on your mesh.

  • Select the left-most column of vertices in the UV-mapĀ  by pressing (and holding down):
ALT
and then right-click
on the left-most column.

On the model we see that one complete edge-loop gets high-lighted.

this is correct.

Now shift, alt, right click, on the right-most column in the UV-editor.

On the model we see that a secnd edge-loop gets selected.

This is not correct!

Because we work with a torus shape we expected,
that the left-most and the right-most column of the UV-map are
assigned to exactly the same loop on the mesh.
We have to fix this later.

Now examine the top most-row of vertices in the UV-map:

ALT- RMB on the top-most row.

You see that the bottom-most row gets also selected.
This is correct. The top to bottom stitching is correct and
behaves as expected.

Let us see, what the baker-tool will create for this object.

Go to:
Render -> Quick Bake Sculpt Meshes
Now examine the resulting sculptie.
Go to:

Object -> Scripts -> Preview Selection

This will create an Object based on the current sculptmap.
This object will show you how your sculptie will later look in your online world.

We see that our object will be rendered to a flat shape.
This is apparently not what we wanted.
And the problem is directly related
to the wrong stitching of the original object.

So how can we correct the wrong left-to-right stitching ?
Apparently the mesh itself is fully correct.
So this is a perfect case for sculptify objects.

But before we actually apply the sculptify tool we have to do a little preparation:
It is important to mark the seams!

Since we have already selected the top-and-bottom edge,
we just mark the corresponding vertices in the mesh as seam. For this we click on:

Mesh -> edges -> mark seam.

Now we have marked the top-to-bottom seam.

Let us define the other seam:
ALT-RMB on the left-most column in the UV-editor.

We again mark the edge-loop as seam.
Now we have marked the left-to-right stitching seam.

We are ready now to re-sculptify the object.
go to object mode.
then select:

object -> scripts -> sculptify Objects.

the resulting object has a correct UV-map, with the correct stitching.

Now let us call the baker tool, and then preview the sculptie.
This looks much better. But we see black spots on the object.
So what is that ?
A closer inspection in edit mode shows, what happens.

You see that near the dark spots the faces intertwine.
This happened because the inner surface and the
outer surface of the object are too close to each other.

You can correct this manually by shifting the vertices a bit such that the
surfaces no longer intertwine. Then the black spots disappear.

You can now do some fine corrections of your mesh,
bake again,
and then your Sculptie is ready for transport to Secnd Life.

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