(Solved) [Blender 2.8] Normal Transfer, a tricky case

bitinn

This is probably not possible, but let us see if there are more fluent users of Data Transfer modifier here.

Goal: transfer the custom normal from this continuous piece onto these 2 split pieces



You might not see it but the difference is normals on split pieces are not smooth like the continuous piece:




I have some experience with Data Transfer modifier, but for this one, strangely, I couldn't get it to work.

Alternatively, if it's possible for me to set a split normal to point to 3d cursor, then I could have fix it without transferring too, but I wasn't able to do that without crashing Blender.

musashidan

Doesn't Meshmachine addon have tools specifically for this?

https://www.youtube.com/watch?v=b7-IDIqjF1k

bitinn

musashidan said:

Doesn't Meshmachine addon have tools specifically for this?

https://www.youtube.com/watch?v=b7-IDIqjF1k

That's cool, but really a high-to-low normal baking, to a texture.

I am facing a low-to-low, split vertex normal transfer.

jakemoyo

You are  able to do this. You'll have to data transfer each split piece individually from the   whole piece and scale and flip it. Make sure you try all the different settings with face corner normals, custom vertex normals etc. But it is doable ive done this exact thing in the past. If you're trying to bake normals onto it it'll never look 100 percent though. The seam will be less apparent up the middle but it will still be there.

musashidan

That's not baking, it's explicit normal transfer low to low. 

Don't know if it handles discontiguous normals though.

gnoop

There is a few things to check first. Be sure object is smooth shaded and auto-smooth check box is checked in.  Guess it's all set already based on your screens.

The next thing is Blender with most of it's transfer ways looks like borrowing normals from source object face normals, not vertex ones. 

Bet it's basically regular ray tracing  from target vertexes to surface of source object along vertex normals.  Nothing extra.    So you  have to tessellate source object pretty densely  the way the face normals beneath your target vertexes have necessary  direction . Better would fall to same polygon there . 

In a word source object shouldn't have  the edge in the same place your target object split resides.

bitinn

Thx for the suggestions, so I went back and tried it again, and it finally worked:

Basically I need to use "Projected Face Interpolated" option here and set both "Max Distance" and "Ray Radius" to a small but workable value (just like when you bake textures). To limit affected vertices I use "Vertex Group" to further limit the transfer to only vertices with normal mismatches.

https://docs.blender.org/manual/en/dev/modeling/modifiers/modify/data_transfer.html

The result looks pretty good: