No objects found to bake from

I’m trying to make a normal map or displacement map from multires.

Here’s what I did: Start with a default cube, add a lvl 5 multi-res, sculpt it, and turn preview subsurfing to 0. I marked seams, and unwrapped the cube.

But now, I go to the render tab, check “bake from multires”, pick “Normals”, and hit bake, but I get the error “No object found to bake from.”

Why does it give me that error? It can’t find the cube or something? How do I fix this?

I’ve uploaded my .blend


NormalMapTest.blend (566 KB)

You need to enable the Preview Multires level – I set it to 5 and the map baked OK, though the result looks a bit suspect in terms of how well it records the sculpting you did.

Whoa you’re right, it bakes now. But … now I’m super confused.

I read this and got the impression that the viewport subdivisions need to be turned off, or at least, the viewport needs to display the low-poly mesh I eventually intend to use.

If I set preview to anything higher than 0, then the cube no longer looks like the low-poly cube. But if I set preview to 0, then “No object is found to bake from”
Also, if I set preview to anything higher than zero, the normal map no longer maps exactly to my UV unwrap because of the smoothing.

Am I misunderstanding something, or is this just how it works?

I get a 404 trying to follow that link you posted to the info.

I haven’t used this feature before, so I can’t comment on such details, it just seemed to me that if you’re baking directly from the multires, then it might need to be enabled for it to have the data necessary for the bake. I agree it seems odd that there’s no “target” low-poly object in this case, and that may be why the normal map looks, well, abnormal. Then again, the process could automatically take the base level shape into account and bake to it from whatever multi-res level is being previewed. I don’t know enough about the innards to hazard a guess here.

However, trying to bake that highly-rounded sculpted shape to a basic cube may just be asking a bit much, it certainly wouldn’t render like the sculpted shape, it’d result in just a cube with some surface features. I think the feature expects a better correspondence between base shape and the multi-res sculpt, since the idea is to add surface details without adding polys, not completely re-shape the base mesh.

Yeah, I’m just using the cube as a simple test to figure out the workflow for normal/bump mapping.

Sorry, I must have mis-copied the link:

Bake from Multires bakes the normals from the highest Multires value to the lowest. ‘0’ [zero] , it seems, is not an acceptable value for this operation. You need to have at least 1 level of multires in preview.

Side note: You might want to consider baking the normal map at 2x or even 4x the size you intend to use and doing some touch up work on it in Gimp or Photoshop and then scaling down before bringing back into Blender. Blender bakes, I find, are unacceptably noisy.

Oh…, In order to keep your Cube a Cube. Don’t do Catmult-Clark subdivision in the Multires Modifier. Click the button to the right, ‘Simple’, instead