Hi Martin,

> 1. New Ubuntu and Mint flavours of linux have a kernel mod
> that enables 32bit platforms to take advantage of systems
> with more than 4gb RAM, does moi see this and use it, or is
> that something done at kernel level ?

I don't know the specifics of this mod, but most likely it's something at the kernel level, probably allowing the kernel itself to use more than 4GB to divide between all available processes. But any one individual 32-bit process will still be limited itself to a 4GB address space, that's just how much memory can be addressed by a 32-bit number so that per-process limit is fundamental to a 32-bit program.

If you are working with large models, one thing you can do in MoI to help is to adjust the display settings to make a coarser display mesh. By default the settings are fairly high to make for a nice smooth looking surface display but on large models higher density display meshes can consume quite a bit of memory. See here for some information about how to adjust the settings to make a coarser (and a bit more jaggedy appearing) but lower memory consuming display mesh:
http://moi3d.com/forum/index.php?webtag=MOI&msg=4196.2


> 2. Has anyone tried rendering with blender/yafaray combination
> with an exported mesh from Moi, is it reliable and stable ?

Yes, some others have used that combination ok before, here are some gallery images done with that method:
http://moi3d.com/gallery/viewitem.php?id=142
http://moi3d.com/gallery/viewitem.php?id=141

But Blender has some problems with importing meshes exported from CAD programs since it does not have the ability to read vertex normals in from the mesh file, which can result in a lower quality shading than with other rendering and modeling programs that are able to read that vertex normal shading data in and use it. As far as I know every other rendering program other than Blender is able to use that information, it seems to be a problem unique to Blender.

See here for some more information on this Blender problem:
http://moi3d.com/forum/index.php?webtag=MOI&msg=4515.3
http://moi3d.com/forum/index.php?webtag=MOI&msg=4272.1

It will still work to import the mesh into Blender but Blender will ignore the vertex normals stored in the mesh file and instead create its own vertex normals for shading just by averaging the normals of the polygonal data. That will tend to make polygonal artifacts appear in the shading.

It can help if you dice your mesh data up into smaller more evenly sized pieces using the "Divide larger than" setting like this:
http://moi3d.com/forum/index.php?webtag=MOI&msg=2833.5

Basically because it does not import vertex normals Blender is set up to only work with sub-d type mesh structures which are all made up of small evenly shaped quads and not things like big polygons next to small polygons (and polygons at sharp angles to one another) like you will typically get with CAD generated meshes. Other rendering programs can deal with the CAD-generated data much better because they use the vertex normals from the file which come from the original NURBS data instead of being approximated from the polygon structure. When those vertex normals are used it helps to make the shading look exactly the same as the original NURBS CAD structure.

So because of this Blender is not really the best renderer to use for MoI data (or any kind of CAD-generated data), and unfortunately so far the developers have shown no interest in fixing it.

- Michael