Fix exact boolean coplanar problem due to inexact transform.

This is an addendum to previous boolean fix, where the object
transformation was "cleaned". Now the operand one is too.
This fixes the issue shown in the video in T82301 when you move
a column around the XY plane with the top and bottom faces
supposedly coplanar with a cube. The transformation matrix when
you do that has a tiny offset in the z component.

1 files changed, 4 insertions, 1 deletions

diff --git a/source/blender/modifiers/intern/MOD_boolean.c b/source/blender/modifiers/intern/MOD_boolean.c
index 8d0c7cd6d49..7ddaf15aaa3 100644
--- a/source/blender/modifiers/intern/MOD_boolean.c
+++ b/source/blender/modifiers/intern/MOD_boolean.c
@@ -340,13 +340,16 @@ static void BMD_mesh_intersection(BMesh *bm,
        * other than 0, -1, or 1 in the scaling part of the matrix.
        */
       float cleaned_object_obmat[4][4];
+      float cleaned_operand_obmat[4][4];
       clean_obmat(cleaned_object_obmat, object->obmat);
       invert_m4_m4(imat, cleaned_object_obmat);
+      clean_obmat(cleaned_operand_obmat, operand_ob->obmat);
+      mul_m4_m4m4(omat, imat, cleaned_operand_obmat);
     }
     else {
       invert_m4_m4(imat, object->obmat);
+      mul_m4_m4m4(omat, imat, operand_ob->obmat);
     }
-    mul_m4_m4m4(omat, imat, operand_ob->obmat);
 
     BMVert *eve;
     i = 0;