This tutorial is for Blender version 2.49b:
» How to export a STL design file
» How to export a VRML 97 design file
STL designs are good for all 3D materials.
Select the object and enter Edit mode (Tab). Select all vertices with A, then press W and select "Remove Doubles". This merges any doubled up vertices that are sitting on top of each other.

You can adjust the distance at which they merge by changing the Limit in Editing (F9), under the Mesh tools tab:

Blender will triangulate your mesh when you export. Sometimes this can cause issues with smooth or curved parts of your model, so to check to see what it will look like, select all vertices and press CTRL-T.
Select all vertices in Edit mode and press CTRL-N and click Recalculate normals outside:

Blender will only export the selected objects, so make sure they are highlighted (in object mode).
Choose File, Export, STL… and save your file:

You’re now ready to...
Your 3D design file must be less than 20mb. If it is not, you can make it smaller by reducing the number of vertices in your model. If you are using a Subsurf modifier, try reducing the number of levels.
Use CTRL+ALT+SHIFT+M to select non-manifold mesh edges, faces and vertices. To make it easier to work on, you can increase the selection by pressing CTRL-NUM+ (+ on the numpad) a couple of times, and hide everything else with SHIFT-H. You can un-hide them again with ALT-H.
Get in touch with us - and attach your design. We'll get back to you as soon as we can with a fix.
topVRML 97 designs are good for Rainbow plaster.
Remember we do not support textures at this time. This means you need to apply your colors by going to Edit Buttons (F9) and under the Link and Materials tab, using the Assign button to assign the current material to selected faces.

Now you’re ready to export ...
Select the object and enter Edit mode (Tab). Select all vertices with A, then press W and select “Remove Doubles”. This merges any doubled up vertices that are sitting on top of each other:

You can adjust the distance at which they merge by changing the Limit in Editing (F9), under the Mesh tools tab:

Blender will triangulate your mesh when you export. Sometimes this can cause issues with smooth or curved parts of your model, so to check to see what it will look like, select all vertices and press CTRL-T.
Select all vertices in Edit mode and press CTRL-N to and click Recalculate normals outside:

Blender will try and export the whole scene (including any lights and cameras) unless you select only the objects you want to export.
Export the objects with File, Export, VRML97 (∗.wrl) and save your file. Please note that there are two versions of VRML. Make sure you use VRML97, which is near the bottom of the list:

Make sure Selection only is highlighted and press OK:

You’re now ready to ...
Your 3D design file must be less than 20mb. If it is not, you can make it smaller by reducing the number of vertices in your model. If you are using a Subsurf modifier, try reducing the number of levels.
Use CTRL+ALT+SHIFT+M to select non-manifold mesh edges, faces and vertices. To make it easier to work on, you can increase the selection by pressing CTRL-NUM+ (+ on the numpad) a couple of times, and hide everything else with SHIFT-H. You can un-hide them again with ALT-H.
You can recalculate normals by selecting all vertices and using CTRL-N. Check they are all facing the right way by turning on Draw Normals under the Mesh Tools More tab in Edit buttons (F9)

Individual faces can be flipped by selecting them and using W, Flip Normals:

Make sure your materials in Blender don’t reference any textures (Image or Procedural.)
Get in touch with us - and attach your design. We'll get back to you as soon as we can with a fix.