Normal map baking yields flat UV image -- what's wrong?

Technical Support Modeling
1

Hi all,

I’m somewhat new to blender and 3D modeling in general.

I’ve been working on UV mapping and normal maps in order to take a high poly surface and wrap it around a low poly model by baking the normals (i.e. to create a game asset). Problem is, whenever I actually bake the normals on to the unwrapped UV map, it gives me a flat and monochrome image (see attached).

My workflow to create a rock:

  1. scale the default cube x2 on y-axis (add a loop cut)
  2. Add modifier --> multiresolution --> subdivide by 5
  3. sculpt mode --> use various brushes to give a bumpy surface (this is the highpoly object)
  4. duplicate object --> move new object to another layer
  5. subdivide the first object down to 1 (this is now the lowpoly object with 40 faces)
  6. apply the multiresolution modifier to both the high and low poly objects
  7. split the window into 2 --> use the new window for UV/Image editor
  8. mark a seam --> unwrap the UV image
  9. select the high poly object --> shift + select the low poly object
  10. bake (using normals and tangent, with “clear” and “selected to active” checked) (margin = 3)
    Rock normal map test.png1356×724 154 KB

I have spent hours of searching to find out how to resolve this problem.

Does anyone know what could cause this?

(here is the blend file: http://www.mediafire.com/?92vzi2rta8msk4h)

2

Does anyone know what could cause this?

Your two object are in two totally different locations.

Move one object to the same location as the other. ALso set smooth shading for both objects or you’ll get a facetted normal map

Attachments

Screen Shot 2012-11-24 at 14.29.03.jpg681×326 32.6 KB

Screen Shot 2012-11-24 at 14.29.36.jpg651×445 32 KB

Screen Shot 2012-11-24 at 14.29.26.jpg683×470 73.6 KB

3

Thanks for the quick response Richard,

Somehow this is still not working for me. I must be doing something very basic incorrectly.

My steps:

  1. I snapped my cursor to selected (the lowpoly model)
  2. snapped the highpoly model to cursor (now on top of the loypoly model, in the same layer)
  3. set both high and low poly models to smooth shading
  4. hit bake

Here is what i got:

new blend file URL: http://www.mediafire.com/?ldm8u95k1rcyy8z

What did i miss?

Attachments

Rock normal map test 2.jpg1366×728 238 KB

4

Download your blend file, open it in blender 2.64, do nothing but press Bake button and I get

Attachments

Screen Shot 2012-11-24 at 14.54.05.jpg691×476 51.2 KB

5

I never really did much with this, so I’m not sure, but does checking “Bake from Multires” make any difference?

6

Haha!

Yeah I re-opened the file and hit bake. Sure enough it worked. Not sure what I did wrong before, but no matter.

Thank you so much! Saved me a lot of frustration.

I have one more question for you about this topic: when unwrapping a UV, does it matter how it actually fits into the UV/Image editor window (i.e. if it’s bigger vs smaller, if it fits the image window better vs having a lot of extra empty space). Does this effect anything when wrapping the high-poly mesh around the low-poly object? (In some tutorials, the teacher spends a decent amount of time fitting the unwrapped UV to the window by playing around with the seams and rotating and scaling the UV components, but never explains why.)

Thank you again, Richard!

7

The more space you use of the image, the more detail you can get. You can spend a lot of time adding details in the high-poly mesh, but if you bake that to a small island on a 512x512 texture, you’ll lose most of it.