Object.ray_cast (and all RNA functions using "ob->runtime") broken in Blender 2.80 #57861

New Issue

Kofi Garbrah · 2018-11-16T04:53:04+01:00

Kofi Garbrah commented

2018-11-16 04:53:04 +01:00

System Information
Operating system and graphics card
macOS X Mojave with GTX 980

Blender Version
Broken: 2.80. 59f0db430a
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

ray_cast_test.blend

**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 [ray_cast_test.blend](https://archive.blender.org/developer/F5579003/ray_cast_test.blend)

Kofi Garbrah commented

2018-11-16 04:53:04 +01:00

Added subscriber: @KofiGarbrah

blender-admin commented

2018-11-16 04:53:04 +01:00

blender/blender-addons#58317 was marked as duplicate of this issue

blender-admin commented

2018-11-16 04:53:04 +01:00

#59791 was marked as duplicate of this issue

blender-admin commented

2018-11-16 04:53:04 +01:00

blender/blender-addons#59790 was marked as duplicate of this issue

Kofi Garbrah commented

2018-11-16 04:56:24 +01:00

This comment was removed by @KofiGarbrah

*This comment was removed by @KofiGarbrah*

Philipp Oeser commented

2018-11-16 10:42:29 +01:00

Added subscriber: @lichtwerk

Philipp Oeser self-assigned this 2018-11-16 10:42:29 +01:00

Philipp Oeser commented

2018-11-16 10:42:29 +01:00

Confirmed, will have a look...

Philipp Oeser removed their assignment 2018-11-16 12:20:34 +01:00

Bastien Montagne was assigned by Philipp Oeser

2018-11-16 12:20:34 +01:00

Philipp Oeser commented

2018-11-16 12:20:34 +01:00

Added subscribers: @mont29, @brecht

Philipp Oeser commented

2018-11-16 12:20:34 +01:00

Hm, seems like since the removal of DerrivedMesh from RNA (79615c5adb) there are a couple of issues.
Checked rna_object_api() and all RNA functions using ob->runtime fail.

rna_Object_ray_cast():

fails (says "Object 'bla' has no mesh data to be used for ray casting")

rna_Object_closest_point_on_mesh():

fails (says "Object 'bla' has no mesh data to be used for finding nearest point")

rna_Object_me_eval_info():

bpy.context.selected_objects- .dm_info("SOURCE") is OK (uses ob->data directly)
bpy.context.selected_objects- .dm_info("DEFORM") fails (returns empty string)
bpy.context.selected_objects- .dm_info("FINAL") fails (returns empty string)

@mont29: any ideas here (assigning to you first)?
or maybe @brecht can comment?

@KofiGarbrah: 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 )

Hm, seems like since the removal of DerrivedMesh from RNA (79615c5adb) there are a couple of issues. Checked `rna_object_api()` and all RNA functions using `ob->runtime` fail. **rna_Object_ray_cast()**: - fails (says "Object 'bla' has no mesh data to be used for ray casting") **rna_Object_closest_point_on_mesh()**: - fails (says "Object 'bla' has no mesh data to be used for finding nearest point") **rna_Object_me_eval_info()**: - bpy.context.selected_objects- [x].dm_info("SOURCE") is OK (uses `ob->data` directly) - bpy.context.selected_objects- [x].dm_info("DEFORM") fails (returns empty string) - bpy.context.selected_objects- [x].dm_info("FINAL") fails (returns empty string) ----- @mont29: any ideas here (assigning to you first)? or maybe @brecht can comment? ----- @KofiGarbrah: 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 ) ```

Philipp Oeser changed title from ~~Object.ray_cast broken in Blender 2.80~~ to Object.ray_cast (and all RNA functions using "ob->runtime") broken in Blender 2.80

2018-11-16 12:21:55 +01:00

Bastien Montagne commented

2018-11-16 14:47:06 +01:00

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))

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: ```lang=python 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)) ```

Brecht Van Lommel commented

2018-11-16 14:57:38 +01:00

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.

Kofi Garbrah commented

2018-11-16 15:05:37 +01:00

Changed status from 'Open' to: 'Resolved'

Kofi Garbrah closed this issue

2018-11-16 15:05:37 +01:00

Kofi Garbrah commented

2018-11-16 15:05:37 +01:00

Thanks for the workarounds! I've marked this as resolved.

Bastien Montagne commented

2018-12-26 17:32:31 +01:00

Added subscribers: @Darcvizer, @MichelAnders

Bastien Montagne commented

2018-12-26 17:33:18 +01:00

Changed status from 'Resolved' to: 'Open'

Bastien Montagne reopened this issue

2018-12-26 17:33:18 +01:00

Bastien Montagne commented

2018-12-26 17:33:18 +01:00

Somehow missed @brecht's comment, indeed think that would be a nice addition, will do that now.

blender-admin commented

2018-12-26 22:48:10 +01:00

This issue was referenced by 61cb1a81a8

This issue was referenced by 61cb1a81a84c8a10c5abfb86011de9ea4bb2aa3d

Bastien Montagne commented

2018-12-26 22:55:09 +01:00

Changed status from 'Open' to: 'Resolved'

Bastien Montagne closed this issue

2018-12-26 22:55:09 +01:00

Bastien Montagne commented

2018-12-26 22:55:18 +01:00

We can even use depsgraph from context, in fact, should work perfect for 99% of usecases ;)

Michel Anders commented

2018-12-27 10:30:15 +01:00

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.

Bastien Montagne commented

2018-12-28 10:20:54 +01:00

Added subscribers: @Vax456, @Sherm, @capnm, @Joefelix, @Dragon.Studio, @JacquesLucke

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Object.ray_cast (and all RNA functions using "ob->runtime") broken in Blender 2.80 #57861