There SDFs in the scene - raymarching - #30 by hofk I have a basic variant for moving an SDF via raycast. Now I have combined raycasting for meshes and SDFs by creating two raycasters. I can move the meshes by clicking on them with the mouse on the vertical auxiliary plane. 07_SDF_ShaderSoloV4 H…

A small cause - a big effect. I am facing the problem with function drawray( sdfPos ){ ... and testVector to get to the bottom of it. Difference SDF to mouse: //let newPos = intersects[0].point.clone().sub(offsetSDF); // Difference SDF to mouse let newPos = intersects[0].point.clone(); 07_SD…

I think using 2 raycasters is making the logic more confusing. The fact that one of the objects is an sdf proxy is a red herring. As far as threejs is concerned, it’s just a box mesh. Can’t you just use 1 raycaster, and check if the hit object is the “box” ?

The box itself is always hit, as the meshes are also in the box. I have therefore already made various attempts to differentiate between the two raycasters. But I have not found a practicable solution. That’s why I’m going to try it with a raycaster soon, but I’m skeptical as to whether I’ll succee…

Oh ok. I misunderstood.. i though there was a mesh box proxy enclosing each of the sdfs? kinda like a bounding box?

In this example without Raycast, for example, I had several boxes. Then an SDF in each box. 03_SDF_Shader const boxParam = []; // boxes for SDFs // define size and position of boxes containing the SDFs from SDF_designs.js // ********************************************************************…

Right. I guess what i’m confused about is why SDF should change the behavior of raycasting at all?

Are you going to pass the ray itself into the raymarcher, and then output some kind of collision data as rgb values or smth?

Is there the possibility of extending box for the sdf’s and changing it’s type to this.type = "sdfBox" and then raycast against the uv of sdfBox where if a pixel has been “discarded” ignore the intersection?

I’m not that much of a raycast expert. I’m approaching it by trial and error. Hence my question post here.

The raycaster knowns nothing about the pixels in the framebuffer. It’s purely geometric. All it knows about is the geometry, and the Object3D transforms. There is no way to get pixels back from the framebuffer without rendering to a rendertarget and reading the pixel data back to the CPU.. You cou…

[image] manthrax: None of this sounds easy Very true! :face_with_spiral_eyes: The scheme for raycast mesh comes from an old example of mine. raycaster - drag and drop

Raycast for meshes and SDFs

Questions

hofk March 19, 2025, 7:30pm 19

A revised and extended version can be found in the Resources Post
SDFs in the scene - raymarching - #31 by hofk

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Raycast for meshes and SDFs

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