Important Note: Please take a minute to read the Tutorial license terms.

preliminary note:

The following documentation is a short reference to primstar 0.9.23 This reference has not been created on behalf of Domino designs. Any erroneous description is entirely due to my lack of understanding. All screenshots have been made with blender 2.49a and primstar 0.9.23 on Windows XP.

This post describes how the primstar baker is intended to be used and what its options are all about. This document is still under development but mostly ready for usage by now. Any feedback is appreciated. Especially if you do NOT understand parts of the document, please report that back!!!

GUI – Bake mesh

The following Popup Menu appears when you select the primstar baker from

Render -> bake sculpt meshes

The default settings of the baker are chosen in a meaningfull way, so you could in most cases end up with just hitting the “bake” button and keep the default settings. But sometimes life is a bit more complicated. In the remainder of this document you will find more in-depth descriptions about what the baker “also” can do for you. I believe it is a good idea to at least know about the options although you may not use them frequently at the end.

Bake

Keep center:

Off(default): When you create a new Sculpt-mesh, its initial object center will be equal to its geometric center. During working on your object in edit mode the object center will always keep at its place. With Keep Center Off (the default settings), the object center will be adjusted to its geometric center before baking. This correction ensures that the sculptmap can use the full color range and thus the highest possible spatial resolution. As a side effect the object center will be corrected as if you had called object -> Transform -> Center new And of course the corrected geometric center is also used for the sculpt-map. In world the geometric Object center is exactly at the rez-location.
On: If this option is checked, then the baker will keep the current object center untouched (in the blender file. In the sculpty the object center will still be placed into the center of the sculpty’s bounding box. But now the bounding box is no longer filled up to the max. Instead of this the used color range is reduced so that the visual object center gets the same offset from the geometric object center as in the blender object. The net effect is, that the spatial resolution of the sculpty degrades more and more as the current object center moves away from the geometric object center.

Notes:

You will want to bake with Keep center On if you need the visual center of the object to differ from the geometric center. This comes in very handy when you create rotating objects like swinging doors, which need their rotation center outside of the geometric center.

Keep Scale:

Off(default): The sculpty will be generated with a cubic bounding box (1 meter each axis). For multiple-sculptie bakes the baker determines the smallest possible bounding box that is capable to wrap around any partial sculptie in the set. Keep scale off typically creates the best results for single sculpties (the full resolution range is used). For multiple sculpty bakes the best possible resolution is calculated for the whole set. The most apparent benefit of a multiple sculpty bake is that all parts fit perfectly together on the level of vertices (all parts align!) while the full resolution is only achieved along the longest BBOX axis. In any case the single sculptie (or the whole set of partial sculpties) needs a rescaling in world.
On: the objects scaling is preserved by reducing the color range accordingly. Only the largest Axis uses the full color range. Hence with Keep scale On the resolution of the sculptie (or set of sculpties) can degrade significantly.

Notes:

For most scenarios a bake without Keep Scale is what you want.
The SL exporter is capable to create a LSL script that takes care about the automatic rescaling of the sculptie (or partial sculpties) in world

Keep seams:

Quote (Domino Marama):

Improvements to the baker have made this option almost useless. When this was added, all vertices falling on a single pixel were averaged to give the final 3D position that was baked to the sculpt map. By selecting “Keep Seams”, any edges that were only part of one face or that were marked as seams disabled this averaging and just the position from the seam is used.

Since then, the baker was improved and now gives preference to the vertices closest to the bottom left of the pixel rather than taking an average. This means that “Keep Seams” only has an effect when the UV layout has multiple edges aligned together.

This situation doesn’t occur with normal sculpties, but the feature was left for cases where manual unwrapping has given problems due to multiple edges clashing. In those cases, you can mark the edge you really want as a seam and enable “Keep Seams” so it’s given priority over the others.

Image

Clear:

On(default): the final image is cleared (all pixels set to [0,0,0] before bake)
Off: The image clearing does not take place.You typically disable Clear when you create your sculptmap in several stages. You might want to first create the left part of a sculpty. In the first bake you will check “Clear” which will leave one half of the sculptmap totally black. Then in a subsequent bake you might want to bake the other half which will fill the former black part of the sculptmap.

Fill:

On (Default): Your mesh might have holes. Such holes typically lead to massive distortions of the final sculptmap as they typically will be rendered to black. The baker can interpolate over the holes thus filling them with a reasonable mesh data. The final result is a full mesh without holes.
Off: Keep holes as they are. (holes rendered to black)

Finalize:

This option prepares the sculptmap in such a way that the mirror option in world will create an exact mirror of the sculpty. As a side effect the resulting sculptmap is more compressible.

On(default): You will enable finalize whenever you bake a sculptie in one step (just bake the sculptmap). This is the typical usage hence On is the default setting.
Off: You will disable finalize only when you are baking a sculptmap in multiple stages. Only in the last baking step finalize should be checked. If you just bake a sculpty in one step, finalize should be checked too.

Notes:

The name “finalize” comes from the fact, that this operation is the last thing that will be done before the sculptmap is ready to use.
In the case you have done your final sculptmap but forgot to finalize it during bake, you still can do that from the UV/image editor by calling the script “image -> finalize sculpty” But beware: finalizing twice will destroy the sculptmap. This is so because the baker uses the alpha channel intermediately as storage area for baking information. When baking with finalize for the first time, this intermediate information is used for the “finalization” and eventually it will be overwritten with the final alpha mask (see below). If you finalize again, the baker interprets the alpha mask as baking data and will severely fail.

Range

Red,Green,Blue settings:

Sculptmaps contain a set of vertex coordinates encoded as RGB-values. Each 3D axis corresponds to one axis in 3D space (x -> red,y -> green, z -> blue) The color range of each axis is [0,255] The default settings will force the usage of the best possible resolution on each axis. that is the reason why sculpties always render with perfect cubic Bounding boxes (all axes of the BBox have length 1m in world). As one matter of fact sculpties normaly can not be made smaller than 1 cm on each axis. And this is where the color range comes into play:

If you reduce the color range, the resulting sculptie will become visibly smaller because only a fraction of the available space is used. You can reduce the color space from 256 values (0,…255) down to a minimum of 4 (e.g. 0,1,2,3) on each axis. Thus the smallest possible cube you can create with this technique would be: 4/256 cm = 15.5 Microns

Note: The bounding box of the sculpty still remains the same as with full color range.
The sculptie only “appears to be smaller”.

Adjust Scale:

Adjust scale is only used in the context of the LSL exporter which also creates a script for scaling adjustments. Adjust scale also only applies when you have modified the color range (see above).

On(default): Due to the reduced color range the visible part of the sculpty will not fill out the whole object bounding box. So at the default size (1 m along each axis) the sculpty will look smaller. With this option checked, the sculptmap will be scaled up to the size it had if the full color range where used.
Off: If the option is turned of, the object will not be scaled to its “default size”, but it will keep the ratios as implied by the ratios of the color ranges.

Alpha

Preview: use a silouette of the shape for better recognition of the sculptmap.
Solid: use no Alpha at all (sculptmap will be seen as is)
Transparent: use full alpha (sculptmap will be rendered fully transparent)
File: use your own alpha mask (upload the mask from your file system)

Default settings

Save : if this option is checked, all current settings will be reused when you recall the GUI the next time within the SAME blender session. If the option is NOT checked, the GUI will always popup with the default settings regardless of what you have used during the previous call of the GUI. With other words: if checked, the GUI remembers what you wanted the last time.
Defaults : if this option is checked, the current settings will be used as default settings. The default settings are preserved over blender sessions.

The Primstar GUI – Bake mesh (link)

Important Note: Please take a minute to read the Tutorial license terms.

preliminary note:

The following documentation is a short reference to primstar 0.9.21 This reference has not been created on behalf of Domino designs. Any erroneous description is entirely due to my lack of understanding. All screenshots have been made with blender 2.49a and primstar 0.9.21 on Windows XP.

The GUI elements

The following GUI pops up when you add -> mesh -> Sculp mesh :

The GUI elements have the following meaning:

Shape

here you can select from a set of basic sculpt types (just click somewhere into the text field). After you clicked on the text field a selection menu pops up. Here you find the set of basic Sculptie types:

At the right hand of the Shape field you find a “File-upload” symbol. If you click on this symbol a file browser pops up. You can upload any sculptmap available on your file system.

Notes:

The Torus X and Torus Z are 2 flavours of Torus with different UV-mapping:

Torus-X: The marked seam on the image (the short seam) corresponds to the upper edge of the UV-map. When you cut along that seam you get the topology of a simple bended cylinder. For example you will use that torus flavor to create a collar.

Torus-Z: Now the marked seam on the image (the long seam) corresponds to the upper edge of the UV-map. When you cut along that seam you get the shape of a car tyre:
 

If you just need a torus, you can use either of them.

Geometry

X Faces: The number of faces in the U plane
Y Faces: The number of faces in the V plane
Radius: only for Torus sculpties. Tells the radius of the inner hole. value range: [0.05 - 0.5]m default value: 0.25
Clean LODs (only for non power of 2 Geometries)

Notes:

Remember that a sculpty always is born out of a simple plane. The numbers above give the numbers of faces in that plane.
The subdivision and the geometry determine the actual number of faces in the sculpty!
“Power of 2″ facecounts always have Clean LOD. Therefore the Clean LOD checkmark is disabled for “power of 2″ sculpties.
If “non power of 2″ facecounts are used, the LOD does no longer make use of “each secnd face” but some times odd LOD-jumps are introduced. If you want to keep hand on how your sculpty behaves with LOD, then you should check “Clean LOD”. If you prefer to keep an equal devided UV-map, uncheck “Clean LOD”.

Citation (Domino Marama):There are some sizes such as the 64 x 128 maps where having Clean LODs enabled is the wrong choice if you want the modelling mesh to match the final sculpt mesh. The “Clean LODs” option will turn black in the GUI if enabled in those cases. It’s also possible to select face counts where neither enabled or disabled will give a match between the modelling mesh and the sculptie. The “Clean LODs” option stays black for both then. You need to adjust face counts for correct adjustment.

Subdivision

Subdivision controls the number of sub hierarchies of nodes in your sculptie. It is directly coupled with the subdivision type
Subdivision type (Subsurf vs. Multires):

Subsurf uses a low poly cage (control points) around your sculptie while the Subdivision count determines how many vertices are manipulated with the control points of the cage.
Multires gives you the option to directly manipulate the mesh according to the first 3 LOD-levels of the Sculptie.

Subdivision type (Catmull vs. Simple):

With Simple the subdivision is calculated linearly. Hence straight edges remain straight but get subdivided into “sub edges”.
With Catmull each level of Subdivision adds more smoothness to the Object.

Notes:

You will use Catmull for smooth rounded shapes. Simple will be most usefull for sharp edged sculpties like cubes..
If you set Levels to “0″ then the number of faces is only determined by the Geometry (see above). In that case neither Multires nor Subsurf will be used for your sculptie.

Mesh type

Quads : all faces are Quads (rectangles)
Triangles: all faces are triangles (not yet implemented)

Note:

Domino stated that the development of triangles can be quickened up if you send him some donations.

Map Size

The map size is a read only GUI element. It shows you the number of pixels in x and in y! Below the top row you also find a table of LOD values. This table tells you how many faces you will have in each LOD level.

Note:

Geometry and Subdivision both influence the face count and the image size!

GUI default settings

The GUI comes with reasonable default settings. In order to support as many use cases as possible, the GUI allows to change the defaults. Below the “Build” button you find 2 checkmarks:

Save : if this option is checked, all current settings will be reused when you recall the GUI the next time within the SAME blender session. If the option is NOT checked, the GUI will always popup with the default settings regardless of what you have used during the previous call of the GUI. With other words: if checked, the GUI remembers what you wanted the last time.
Defaults : if this option is checked, the current settings will be used as default settings. The default settings are preserved over blender sessions.

General notes

The following notes may help you to understand some of the quirks of the GUI:

Sometimes GUI elements turn black. This is generally meant as warning. You need to review the settings and be sure that what you set is what you mean. One typical scenario is when you have selected non power of 2 face counts. In that case the “Clean LODs” checkmark turns black. That means: “Take care here! You may need to choose if you want Clean LOD’s or not…”
The Clean LODs Checkmark is only relevant when you use non power of 2 maps.
Independently of the used facecount, any generated sculptmap will always have power of two dimensions. The dimensions used will always be shown in the Map Size field.

If in doubt, please attach your question(s) to this Post or tell me about any missleading parts and or any necessary corrections. I will update this reference as needed.

Have fun,

Gaia