Clipping issue with SVGRenderer

[doge8000]

Description

2025-10-22.06-17-54.mp4

I tried disabling frustum culling, to no avail.
Using the latest version (r180)

This also happens with the old deprecated CanvasRenderer, so I’m thinking the problem may come from Projector.js

Reproduction steps

Set up a scene with SVGRenderer, a camera, and a single mesh (I used a 10x1x10 one)
Rotate/move the camera around and you should notice triangles from the mesh disappearing and reappearing

Code

Check the jsfiddle

Live example

https://jsfiddle.net/jeqo09y4

Screenshots

I included a video

Version

r180

Device

No response

Browser

No response

OS

No response

[Mugen87]

The problem is that triangles are not clipped (something that you get for free when rendering with WebGL/WebGPU). I believe this could be fixed by implementing a clipping algorithm (e.g. Sutherland-Hodgman) in Projector.

However, I'm not sure it's worth doing this. CanvasRenderer has been removed in 2018 and I'm not sure SVGRenderer is still a useful tool. It is barely qualified as a fallback when WebGL 2 isn't available (three.js requires WebGL 2, WebGL 1 isn't supported anymore). Maybe it would also be an option to remove SVGRenderer and Projector?

If this is about SVG rendering, SVGs can be imported via SVGLoader in WebGL/WebGPU applications.

[doge8000]

The problem is that triangles are not clipped (something that you get for free when rendering with WebGL/WebGPU). I believe this could be fixed by implementing a clipping algorithm (e.g. Sutherland-Hodgman) in Projector.

However, I'm not sure it's worth doing this. CanvasRenderer has been removed in 2018 and I'm not sure SVGRenderer is still a useful tool. It is barely qualified as a fallback when WebGL 2 isn't available (three.js requires WebGL 2, WebGL 1 isn't supported anymore). Maybe it would also be an option to remove SVGRenderer and Projector?

If this is about SVG rendering, SVGs can be imported via SVGLoader in WebGL/WebGPU applications.

Hey thanks alot for your reply
How would one go about implementing a clipping algorithm in Projector? I don't mind (trying, lol) to make a fork, but I'm a little lost.
Also, it's not for SVG rendering. I use SVGRenderer as a fallback when WebGL1/WebGL2/WebGPU is unavailable.

[Mugen87]

I use SVGRenderer as a fallback when WebGL1/WebGL2/WebGPU is unavailable.

What kind of materials are you using such that a SVG fallback is acceptable for your users? Just curious about your scene setup.

Besides, do you have any stats about how many of your user devices do not support WebGL 2?

[doge8000]

I use SVGRenderer as a fallback when WebGL1/WebGL2/WebGPU is unavailable.

What kind of materials are you using such that a SVG fallback is acceptable for your users? Just curious about your scene setup.

Besides, do you have any stats about how many of your user devices do not support WebGL 2?

My goal is to support as many devices/systems as possible, even really old ones.
For example, Windows XP doesn't support WebGL in any way (or atleast I haven't figured it out lol), so SVGRenderer is necessary.
Now will alot of users play on XP? No, obviously not.
But I don't really care, I just find it fun trying to achieve as best of compatibility as I can.

[Mugen87]

Support for XP has been ended in 2014. Using it now is by no means a valid use case.

I personally see no reason to continue the support of SVGRenderer and Projector and vote to deprecate and eventually remove both components. Maintaining this stuff costs time and effort like the discussion of this issue. If apps want to use SVG or Canvas2D as a fallback for 3D, they should implement this own their own. In my view, they are not appropriate as a fallback. Asking users to upgrade their OS/hardware so they can use WebGL2 makes more sense to me.

[doge8000]

Support for XP has been ended in 2014. Using it now is by no means a valid use case.

I know, that's why I used "I just find it fun" as a justification

Maintaining this stuff costs time and effort like the discussion of this issue.

If my issue bothers you feel free to close it lol. I just wanted to report a bug.

[Mugen87]

Sorry, I didn't want to make the impression that I'm annoyed about this issue. This issue is in fact a good opportunity to clarify if the maintenance of SVGRenderer and Projector is still worth it and whether we should guide users towards other (better) solutions.

[doge8000]

Sorry, I didn't want to make the impression that I'm annoyed about this issue.

It's OK

This issue is in fact a good opportunity to clarify if the maintenance of SVGRenderer and Projector is still worth it and whether we should guide users towards other (better) solutions.

I personally dislike WebGL1/Context2D support having been removed (though I definitely understand why it was done), but I can agree with you that it would be fair/logical for SVGRenderer/Projector to also be removed. Its code is almost the same as CanvasRenderer.
Would love it if clipping was implemented before it's deprecated/removed though lmao

[Mugen87]

@gkjohnson Does your pathtracer maybe contain a clipping solution for triangles? I would expect a function like:

clipTriangle( triangle, frustum ) {

}

This function would return an array of triangles with these results:

• 0 triangles if the triangle is completely out of view
• 1 triangle if it is full in view (the unchanged triangle)
• 2 or more triangles representing the clipped triangle.