I want do simple voxelization 3D triangle. And search simple algorithm.
Filling all triangle square small boxes. Each box have size(XYZ) 0.1,0.1,0.1 and 3D position XYZ.
Get array boxes data.
And not using octree or k-tree.

There's a very simple idea that works. I implemented it in the older version of my language.

The idea is to use the midpoint to find the voxels it touches and assign them the texture color at that location.
You have to be careful to ensure the midpoint calculation converges because you need to stop when the recursion returns the same point.

I generate an octree from the voxels, but when it's generated, it's just an array of voxels. To generate the octree, I order them using Morton's sort order, and this grouping is the octree itself.

Here's the code:

https://github.com/phreda4/r4/blob/master/r4/3d/voxobj.txt

the algo is

rectri(tri):
if tri == tri_ad → setvox
else:
M01 = midpoint(V0, V1)
M12 = midpoint(V1, V2)
M02 = midpoint(V0, V2)
rectri( tri(V0, M01, M02) )
rectri( tri(V1, M01, M12) )
rectri( tri(V2, M12, M02) )
rectri( tri(M01, M12, M02) )

I thinking Bresenham's line algorithm for 3D.
https://www.geeksforgeeks.org/python/bresenhams-algorithm-for-3-d-line-drawing/
And filling triangle many lines form boxes.

Bresenham's line algorithm for 2D very simple.