Mesh distance query

[lightmap]

Hello

Is there some engine functions to have kd/octree, voxelisation, sdf?

if not, do you have any plans on integrating it? no one asked for this?

thanks

[silent]

lightmap

Could you please elaborate on this? What do you want to achieve with SDF? Right now we don't have any plans to do this (as well as zero requests).

Thanks!

[lightmap]

automatic mesh-mesh intersection detection

,convex shapes not the case due mesh complexity

,no manual shape annotation

so, probably, voxelization is best candidate, and for medium/large models there must be some acceleration structure

[silent]

There is a separate spatial tree for intersections / collisions speedup (however, it's limited mostly to the MeshStatic objects, not for Skinned / Dynamic since they are often changes).

Do you have a mesh examples that can't be represented with convex shapes (screenshots or FBX)? If you have a test scene where you have some intersection / collision issues - could you please share it with us so we can check if that can be improved in the future SDK versions?

Thanks!

[lightmap]

as I can see, spatial tree works on node level, or there is one on mesh triangle level?

example could be two U-shaped meshes where convex do not let insert one in another without collision

[silent]

Indeed, there are different spatial trees for different purposes plus a separate tree for the triangles that should be involved in collision / intersection.

You can always approximate geometry with multiple convex shapes (there is an addon for blender, not sure if it' still compatible with the latest versions) to reduce triangles count as much as possible.

[lightmap]

Thanks, interesting link

how to use spatial tree for mesh triangles?

how to query in which spatial tree node triangle are? and its bounds

found only three methods in https://developer.unigine.com/en/docs/2.7.3/api/library/engine/class.world

and none in https://developer.unigine.com/en/docs/2.7.3/api/library/objects/class.objectmeshstatic

some samples or function names?

Edited January 15, 2019 by lightmap

[silent]

There are no additional steps required, this tree automatically created on a first intersection / collision. It works independant from the other trees. Unfortunately, there is also no visualization available (there is no world_show_spatial console command analogue for intersection / collision).

[lightmap]

Then how to access spatial tree or its results?

[silent]

The result of spatial tree usage for intersections / collisions is  basically a collision detection between objects (or detection may fail if objects are not collided). This structure is created for internal speed up.

[lightmap]

if separate spatial tree for collisions speedup (limited mostly to the MeshStatic objects) give result for collision detection between objects, then how to get this collision detection ?

[silent]

Just use engine physics and simulate objects movement. Here is the more detailed explanation:

• https://developer.unigine.com/en/docs/2.7.3/principles/physics/collision/
• https://developer.unigine.com/en/docs/2.7.3/code/usage/intersections/index

Thanks!

[lightmap]

Thank you for all your details