System Information
Operating system and graphics card
macOS X Mojave with GTX 980
Blender Version
Broken: 2.80. 59f0db430a9
Worked: no solution
Short description of error
Object.ray_cast is broken in Blender 2.80.
I have attached a blend that contains a simple ray_cast that works in 2.79 and fails in 2.80. Run blender from a console to see the error messages.
Exact steps for others to reproduce the error
Click Run Script to see the result of ray_cast in Blender 2.80
Hm, seems like since the removal of DerrivedMesh from RNA (rB79615c5adb46) there are a couple of issues.
Checked rna_object_api() and all RNA functions using ob->runtime fail.
rna_Object_ray_cast():
rna_Object_closest_point_on_mesh():
rna_Object_me_eval_info():
@Bastien Montagne (mont29): any ideas here (assigning to you first)?
or maybe @Brecht Van Lommel (brecht) can comment?
@Kofi Garbrah (kgarbrah): As a (temporary) workaround for this report you can create a BVH manually and raycast that:
from mathutils import Vector
from mathutils import Matrix
from math import *
from mathutils.bvhtree import BVHTree
def bvhtree_from_object(ob):
import bmesh
bm = bmesh.new()
mesh = ob.to_mesh(bpy.context.depsgraph, True)
bm.from_mesh(mesh)
bm.transform(ob.matrix_world)
bvhtree = BVHTree.FromBMesh(bm)
bpy.data.meshes.remove(mesh)
return bvhtree
mesh = None
for obj in bpy.context.selected_objects:
if obj.type == "MESH":
mesh = obj
if mesh == None:
bpy.ops.mesh.primitive_cube_add(location=(0,0,0))
for obj in bpy.context.selected_objects:
if obj.type == "MESH":
mesh = obj
startRay = Vector((-2,-2,-2))
endRay = Vector((2,2,2))
p = endRay - startRay
distance = sqrt(p.dot(p))
direction = p / distance
print( "start", startRay, "end", endRay, "distance", distance, "direction", direction )
bvhtree = bvhtree_from_object(mesh)
ray = bvhtree.ray_cast( startRay, direction, distance )
print( "Hits:", ray )Imho there is no bug here… that has more to see with how blender/depsgraph/CoW work now in 2.8. Original data (from Main, of bpy.data in python) is not supposed to have evaluated stuff, although we do 'backport' a few things for objects…
You should use context's despgraph object, something like:
start_ray = (-2, -2, -2) dir_ray = (1, 0, 0) depsgraph = bpy.context.depsgraph for obj in bpy.context.selected_objects: if obj.type == "MESH": obj_eval = depsgraph.objects.get(obj.name, None) if obj_eval is not None: print(obj_eval.ray_cast(start_ray, dir_ray))
I would expect this ray cast function to get a depsgraph parameter, which it will then look up the object in. That will at least make it more clear to users what is missing.
Somehow missed @Brecht Van Lommel (brecht)'s comment, indeed think that would be a nice addition, will do that now.
We can even use depsgraph from context, in fact, should work perfect for 99% of usecases ;)
Just tested it with the daily build (blender-2.80-e4dbfe0a98c1-linux-glibc224-x86_64) and repeatedly ray casting on the bvh now works but if I invoke the operator again (and create a new bvh from the same object) I get a segmentation fault. I'll create a separate bug report that references this one just in case this is not related.