3dsmax always grabing distance geometry when baking

jocose

I'm trying to bake a simple high and low poly model.

I have tried using a cage, and offset. I tried lowering the offset and shrinking the cage to the lowest possible value.

It always picks up on geometry in the distance, and I can't figure out why. Is there some sort of setting I need to enable?










Area highlighted in red should not be there, its distant geometry from the other side of the model.

Piflik

Well...since there is nothing else to hit, it hits the parts on the other side of the model...that Low really low...Max casts its rays from the cage to the geometry and uses the first hit (I know it says to use the furthest hit, but that is the furthest from the surface of the low...so it is the first hit of the ray...at least as long as the highs are between the cage and the surface...if the high is beneath the surface of the low, the used hit is also the first, although it is closer to the surface)...if there is nothing to hit before the ray reaches the other side of the model then that is what the ray registers...baking without a cage using offset will also not change a thing, because that only determines what distance from the surface the rays are shot from...

One thing you can try, is assigning Material IDs to the Low and make sure the areas that you don't want to be seen by a certain face have different IDs and then check the 'Hit only matching Material IDs' option...

jocose

I was able to get around this by baking in xnormal instead. There is an option in there called "closest hit if ray fails" if I unchecked that the issue goes away. Its too bad there isn't anything like this in max. If someone knows of something please let me know.

Mark Dygert

I'm not sure if it would change much but in projection options you could try changing "resolve hit" to closest instead of furthest.

Something tells me you might still get wonky results... but never hurts to test it out if you have time.

Piflik

'Closest' and 'Furthest' only affects Highpolys between the Lowpoly and the Cage. As soon as the Ray crossed the Lowpoly's surface, it will always use the first hit. At least that is what my short tests established...might need verification

jocose

Yeah closest and furthest don't affect the issue one bit. Still pops up. Just appears to be the way max handles things.

r_fletch_r

This is hacky and may need some testing before you trust it but It seems to work just fine.

Make an wedged clinder inside the object to occlude the other side.
Add the cylinder to the list of render meshes.
Switch your renderer to menatal ray and add an A&D material to the occluder.
Switch back to Scanline and render.

The rays hit the occluder object in the center and stop but cant be shaded becuase scanline cant handle Mentalray shaders. so you just get a flat blue in the normal map.