Over the last few weeks at the studio I’ve been working in Blender alongside 3DS Max and I’ve needed to export 3D bézier curve (spline) data between the two apps. There were a few occasions, such as exporting a logo that I’d cleaned up in Blender from a 2D SVG, and also some 3D animation paths that I’d been working on. While there are a lot of options for exporting other data such as meshes, there’s very little around to facilitate transferring 3D curves between packages.

Wavefront OBJ is supposed to support curves as part of the spec, but functionality is extremely limited, and it’s so rarely used that I can’t find any apps or plugins that actually bother to support this area of the spec. I read somewhere that Autodesk’s flagship format FBX is supposed to include curve data, but in my tests, neither Max or Maya would export curves to FBX anyway, so it looked like they just didn’t bother support it. This makes it a no-go regardless of whether the up-and-coming FBX exporter for Blender supports it or not.

I thought I’d quickly share a less conventional usage of some of Blender’s newer features that’s been sitting around on my desktop for a while now. A few months ago, it was (my girlfriend) Kat’s birthday and I thought I’d have some fun and make a simple pop-up card, rather than just buying one. Of course after thinking about it for a little while, my curiosity got the better of me and I set about to make it in CG.

It’s just a simple tree, based on the design of a ring of hers. I traced the shape, making sure it was kept in two flat halves, unwrapped it, and sculpted on a bark-like surface. Then, I added a plane with a dirt texture, added some grass, and set up some lights. From there it was just a matter of doing a full render bake to texture, leaving me with a grass image from above, and the unfolded, textured tree. I saved out the baked textures, printed them on to card, cut them out with a scalpel and wrote a message. I had no idea if it would work or not, but I think it came out all right in the end.

Unfortunately, ever since their inception, modifiers in Blender haven’t let you animate their settings. This is a real pain, and a motivational hurdle against people making lots of nice new modifiers like ‘bend’, ‘twist’, ‘taper’, etc. I really hope this gets addressed soon, but until then, here’s an ugly workaround which will let you animate modifiers using the bPython API.

Basically, you need to create a dummy object that you will animate in a simple manner just so you have an editable Ipo animation curve. From there, use a scriptlink set to onFrameChange to read that Ipo and manually set the modifier paramater you’re interested in to the curve’s value at that point in time. You can download my demo .blend file to see how this works (remember to enable script links in the scripts button tab), or check the demo video below to see an animated Decimate modifier.