Page MenuHome

Baking ray distance do not work.
Open, Confirmed, MediumPublic

Description

System Information
Operating system: win7x64

Blender Version
Broken: 2.80 (sub 47), a0f2923fd821, 2019-03-08 21:52
2.79 main too

Short description of error
Baking emissive from object causes strange additional lines.

With cage it becomes even worse

Exact steps for others to reproduce the error
Here the file. Try to bake Emissive from Donor to Recipient with Cage or without

Details

Type
Bug

Event Timeline

Vyacheslav (hitrpr) added a comment.EditedMar 10 2019, 5:45 PM

Ok. It seems, that ray distance do not work for backface and inside of mesh. So cap and border baked on the bottom. And side was baked on the top:

Here the file with success baking

And i forced to put cage inside recipient.
Should it work this way?
Why ray distance do not work at all?

Vyacheslav (hitrpr) renamed this task from Baking artefacts object to object to Baking ray distance do not work..Mar 10 2019, 6:04 PM
Vyacheslav (hitrpr) added a comment.EditedMar 10 2019, 8:06 PM

As I found it works now back way: rays shooting from selected to active and hits inner cage.
Ray distance is not working at all.
Ofcourse cage extrusion is not working with backray: it extrudes only outside as it should.

Sebastian Parborg (zeddb) triaged this task as Confirmed, Medium priority.Mar 14 2019, 2:41 PM

I can confirm that ray distance doesn't seem to work.
No matter what distance the bottom face of the active object will hit the top of the bake object even though the rays should be able to reach.

At least that is what I think should happen by reading the manual: https://docs.blender.org/manual/en/dev/render/cycles/baking.html?highlight=ray%20distance

@Sebastian Parborg (zeddb), I felt that is something wrong before manual. Then I read it. And it is still not working as in manual or as expected(intuitive way).

There should be a rewriting of the manual concerning "ray distance", because it's not clear what the difference is between "ray distance"("cage" not checked) and "cage extrusion" ("cage" checked):
https://blenderartists.org/t/baking-with-cage-ray-distance-vs-extrusion/681424

Could it have to do with split vertex normals as explained generally here (left image):
http://wiki.polycount.com/wiki/Texture_Baking#Cages

This could be the case since the blender manual (https://docs.blender.org/manual/en/latest/render/cycles/baking.html)
writes for "cage extrusion":

"The inward rays are casted from a version of the active object with disabled Edge Split Modifiers."

Then, "ray distance" would automatically create a cage object but without removing any Edge Split Modifier like "cage extrusion" does?

NOTE: I've tested it and didn't find the Edge Split Modifier beeing removed with Cage Extrusion active (Blender 2.8 Beta). Marking edges as sharp always affects Cage extrusion (even without Edge Split Modifier)

According to Blender's source code in ui.py (blender-git\blender\intern\cycles\blender\addon), lines 1866 to 1871,
"ray distance" also is some kind of cage extrusion:

col.prop(cbk, "use_cage", text="Cage")
       if cbk.use_cage:
           col.prop(cbk, "cage_extrusion", text="Extrusion")
           col.prop(cbk, "cage_object", text="Cage Object")
       else:
           col.prop(cbk, "cage_extrusion", text="Ray Distance")

If I understand it right, the manually created cage object replaces the cage object created automatically "extrusion", since the Blender manual writes:

"Object to use as cage instead of calculating the cage from the active object with the Cage Extrusion."

Member cgCody on blenderartist (link above) sees "extrusion" as on offset to the manually created cage object.

If "ray distance" and cage "extrusion" aren't the same, is there an example to illustrate this?

Vyacheslav (hitrpr) added a comment.EditedFri, May 17, 4:15 AM

Thanks for explanation, but in this specific case only cage/extrusion fail, because there is no ray-limit.
As I can understand, it should work like this:

Purple is size of manual cage or extrusion. Black is object with semitransparent parts (baking source) and length of cyan ray will prevent backside baking.

Also there should be such image in the manual. It will work much better than hundred words. And I can do nice scheme, if you need.