This tutorial describes how to export almost any object from blender to sculpted SL prims,
without using a script. I hope it can inspire someone to write a nice script to make it easy.

This was made possible thanks to all the information gathered from the following pages:

http://wiki.secondlife.com/wiki/Sculpted_Prims
http://wiki.secondlife.com/wiki/Talk:Sculpted_Prims
http://wiki.secondlife.com/wiki/Talk:Sculpted_Prims:_3d_Software_Guide#Blender

http://amandalevitsky.googlepages.com/sculptedprims

and thanks to discussions and ideas sharing with tomHa Zymurgy, Eddy Striker and Ziggy Puff.



I made this tutorial as explanatory as I could, but it assumes that you are relatively conmfortable with Blender, and have some notions about  SHAPE KEYS, which are a powerfull feature allowing us to morph a mesh, while preserving its uv-space.

If its new for you, take a look at this excellent page to figure out SHAPE KEYS,
and if you are unfamiliar with blender, I suggest you first take a tour on http://www.blender.org/tutorials-help/


First of all you need minimum a blender 2.43 version, available here, and a working python 2.4.4 installed and configured, because we want to use some uv projections scripts.



Lets dive into it and create a fresh new file ( CTRL-X ) :



 your layout might differ from mine,  but process will be the same.


We add a nurbs sphere for instance. Again, we could start from anything, but, I choosed a nurbs sphere to make things easier here.
( SPACEBAR, Add, Surface, Nurbs Sphere ) :





I played with knots and created a lovely hearth ^_^ :

 



Lets convert this into a mesh first ( ALT-C):

 



Our goal is to obtain a nice homogen uv map from this object, to project its XYZ coordinates, coded as RVB values of an image.
This shape is relatively simple, but yet, if you try to just use blender's default spherical uv mapping, the uv map won't be correct for our purpose.

First lets give our object the good topology, by changing the pole vertices to rings :

Delete the two poles:


Extrude and size the resulting rings to this:





The main idea is to temporarily deform the object to a sphere, so that we have a perfect spherical uvmapping, then revert to the original shape, while preserving the obtained uv space.

This is where shape keys come to our help.
Lets first add a base key ( Buttons Window panel, F9) , beware, you need to be in OBJECT MODE ( TAB) before adding the button !





This will be the original shape of our mesh, said 'basis', that shape that we want to export:



Lets add another shape key, on which we will work while preserving the original. This shape key will be called 'Key 1'





Now we switch back to EDIT MODE ( TAB) to play with the vertices of KEY 1 shape key :




To shape the heart into a sphere, select all vertices, ( AKEY ) , then use 'TO SPHERE' button in EDIT BUTTONS:



You will be prompted for an amount of deformation, keep it to the 100% value:




Now we have a better candidate to spherical projection, isn't it ?



I take a pause to explain a little bit about shape keys if its still unclear for you. Hit TAB to return to OBJECT MODE:




As you can see, OBJECT MODE shows the BASIS SHAPE KEY. You can control the amount of KEY 1 influence with a little slider, which is at zero by default :



This is pretty similar to appearence sliders in SL, nose lenght, feet size and so on. We can add as many shapes as we like, and mix their influences on result with sliders. But lets get back to work.

In the side view ( 1 or 3 ), hit  U KEY to get projection menu and select ' PROJECT FROM VIEW ( BOUNDS )' :





This should give us the following uv map in the UV/Image Editor :



You'll say, not very interesting, but this step was just to initialize uv space height and width.



Now back to UV FACE SELECT area, select the "closest" face to make it active :





Now select all faces, hitting A KEY twice :





From the projection menu (U KEY) , choose FOLLOW ACTIVE, with the NONE option :

   


Now our projection should be :



almost...still two little steps and all is done

In the UV/ Image EDITOR, select the ' QUADS CONSTRAINED RECTANGULAR' UV OPTION:



This assures that each quad is a rectangle. Unexpected with such a name uh ?

Lets move all uv's a little (A then G KEY) to force blender to make the transformation :




Back to the projection menu, lets repeat projection, with FOLLOW ACTIVE, NONE option again :




Now we have :



Not too bad. Just a matter of sizing , and we're done with that part :

Select 'LAYOUT CLIPPED TO IMAGE SIZE' from the UV options in UV/Image editor:




Size X first ( S KEY, MMB or X ) :



Then size Y ( S KEY, MMB or Y ) :



Pfew ! I wish blender had an option to do all these steps in one click... but we have our perfect uv space !



Now we will apply a new material to our object to bake displacement map on our texture.

Add a new material :


The process of setting the material is described very well here so I won't repeat it here.



Once you have your material set like Amanda said, make sure you revert to the BASIS SHAPE KEY , setting the KEY 1 slider to ZERO:




And BAKE your result, making sure TEXTURE option is selected ( Render Buttons, F10 KEY ) :





WOOT ! TADAAAA :






Just save your nice image as TGA, and you can go have a deserved nap :

         

I made the final texture available here , aswell as the blend file




OK.

This looks like a bit complicated to export a stupid sphere based nurbs heart.

But the method is just the same for any other shape, provided that it has no holes, and that you change the poles to rings.
If your shape is complex and has non convex parts, you will need to adjust vertices before using the 'TO SPHERE' feature on the second Shape Key, to avoid edges overlapping. This is a painful work to do by hand with flatten and smooth vertices features , that is why I choosed to use the heart for the tutorial instead of something more tricky like poor Suzanne.

I made this Suzanne export using the exact method described above, and this metaballs export too.


As a conclusion :

If someone was able to write a script that inflates a mesh to a sphere without overlapping edges, much like when you blow a bubblegum, and if someone could write another script to make the perfect spherical uv projection easy, and if a third could merge all this into one single script, I think we would have our blender export done :)


And as a request,

PLZ LL fix 1.16 for linux users like me ! I still couldn't log into beta with it, nor rezz anything and I am FRUSTRATED  ^_^ !


This is why I made my blender previewer better btw.