Why raycastTraverse use `Object.getPrototypeOf(c).raycast`? about 3dtilesrendererjs HOT 6 CLOSED

Raycasting is handled with a custom traversal algorithm so the raycast function on each mesh is replaced with a custom one on load to avoid redundant raycasting work. It's the only way to disable raycasting on an object in three.js.

Can you explain in more detail what you're trying to do? Why do you need to replace the raycasting function?

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First, I still cannot get it why the code is written like Object.getPrototypeOf(c).raycast rather than c.raycast. I assume that it can also work with your custom traverse raycasting design above.

In my project, 3DTiles data is BIM which is so heavy and large. Even the raycasting has been optimised, the performance is still not good. In fact, I'm gonna replace raycast function to BVH. I noticed that you are also the BVH author, is there an elegant way to deal with it?

from 3dtilesrendererjs.

First, I still cannot get it why the code is written like Object.getPrototypeOf(c).raycast rather than c.raycast. I assume that it can also work with your custom traverse raycasting design above.

As I said the raycasting performs custom traversal by overriding the root "raycast" function and it's required to replace the existing raycast function with an "empty" one so duplicate raycasting is not performed. The prototype raycast function is retrieved when leaf nodes are traversed to so we have the associated raycast function associated with the object type. Because we replace the original raycast function with the empty one it's no longer available.

In my project, 3DTiles data is BIM which is so heavy and large. Even the raycasting has been optimised, the performance is still not good. In fact, I'm gonna replace raycast function to BVH. I noticed that you are also the BVH author, is there an elegant way to deal with it?

three-mesh-bvh suggests overriding the prototype of Mesh in the documentation which will work just fine here since the prototype is modified:

Mesh.prototype.raycast = accleratedRaycast;

It's possible to add something that allows for more control over this but I'd like to avoid it if possible. At least this limitation should be listed in the documentation, I'd think.

from 3dtilesrendererjs.

three-mesh-bvh suggests overriding the prototype of Mesh in the documentation which will work just fine here since the prototype is modified:

Mesh.prototype.raycast = accleratedRaycast;

I don't think this is an elegant way. Using c.raycast is a better way. I only want to modify raycasting on some meshes, not all. Mesh.prototype.raycast is a global affecting API. This may cause some compatible issues when using some other third-party libaraies

from 3dtilesrendererjs.

I don't think this is an elegant way. Using c.raycast is a better way.

I'm not interested in repeating what I've already stated previously. If there's something specific you don't understand about why the current approach is being used I'm happy to answer. But statements like this are not helpful.

I only want to modify raycasting on some meshes, not all.

I won't be dealing with hypothetical situations. Please be specific about what function you're replacing the raycast one with and why.

The current "optimizedRaycast" and "firstHitOnly" options enabled by the overwritten raycast functions provide a 2-5x performance improvement over the naive raycast approach in some cases. And it would be even higher (4-10x or more) if there were a way to get rid of some other unnecessary three.js overhead.

from 3dtilesrendererjs.

I'll close this until more information or details can be provided on the purpose. Ultimately changes need to be made in three.js to support this. Or a custom raycaster solution needs to be provided, which I don't think is an elegant solution.

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