I am currently trying to discover if any background object is in front of my foreground object (obj.name = 'Mhx2test') with blenderpython. To do this, I use the ray_cast method. So what I do is sending a ray from the camera directed to the foreground model what should return a position I can compare with the position of the foreground model to determine if the first intersection was with the foreground model or any other background model. I built a very basic scene with a Cube being between the camera and the foreground object:
So the camera view shows that blue cube in front ob the foreground model. Sending a ray towards the foreground model should thus return the nearest intersection point with the cube. However when I run the following code it doesn't discover any intersection, i.e. the result is 'False'.
def detect_nearest_intersection(): scene = bpy.context.scene me_tmp = bpy.data.meshes.new(name="~temp~") obj_tmp = bpy.data.objects.new(name=me_tmp.name, object_data=me_tmp) scene.objects.link(obj_tmp) scene.update() ray_cast = obj_tmp.ray_cast camera = bpy.context.scene.camera mod = bpy.data.objects['Mhx2test'] direction = mod.location - camera.location; direction.normalize() result, location, normal, index = ray_cast(camera.location,direction) print("Raycast from %s to %s" % (camera.location, mod.location)) print("Result: %s, location: %s, normal: %s, index: %s" % (result,location,normal,index))
Here is the output of the result:
Result: False, location: <Vector (0.0000, 0.0000, 0.0000)>, normal: <Vector (0.0000, 0.0000, 0.0000)>, index: -1
The ray_cast documentation from here:
ray_cast(origin, direction, distance=1.70141e+38) Cast a ray onto in object space Parameters: distance (float in [0, inf], (optional)) – Maximum distance Return (result, location, normal, index): result, boolean location, The hit location of this ray cast, float array of 3 items in [-inf, inf] normal, The face normal at the ray cast hit location, float array of 3 items in [-inf, inf] index, The face index, -1 when original data isn’t available, int in [-inf, inf]
I am using blender v2.78 (former versions implemented the ray_cast as ray_cast(start,end), v2.78 seems to use ray_cast(start,direction))