Making a geometry or volume from a wedge of a sphere

Questions
1

Hello! I was wondering if anyone would have a way to make a geometry that would in essence be a wedge of a sphere. It would have some delta theta/phi, map out four corners, and four lines going back to the origin. It would also have some start and end radius.

similar to this picture here
image

I was thinking of possibly using the section of two spheres and connecting them with four lines?

2

here is something to get you started

2 Likes
3

Yes, this is a promising direction of thinking.

Instead of four lines, I’d suggest to use four THREE.RingGeometry objects, so that your shape looks like a solid object.

5

Thank you for the start!!

I should have mentioned I would like the final geometry or volume to be one mesh, if possible?

Is there a straight forward way to accomplish that?

I want to be able to raycast into the final volume

6

thanks, that’s is a good suggestion! As I posted above, I’d like to take all the points and make one final volume with them if possible

7

That’s what mergeGeometries does. (BTW, if it is only for raycasting, you do not need a single mesh.)

1 Like
8

hmm okay. I apologize about my (lack of) knowledge with threejs ray casting.

right now I’m using a cone with

const coneGeom = new ConeGeometry( 2, 2, 4 );
const coneMaterial = new MeshBasicMaterial( {color: color, 0x00FF00} );
const coneVol = new Mesh( coneGeom, coneMaterial );
... raycaster stuff ...
const intersects = raycaster.intersectObjects([coneVol]);

are you saying I can achieve this with this example

9

Actually, I stand corrected. Only two of the four sides are rings, the other two are not planar. So, my new suggestion is to use a spherical cube – this is a cube which Cartesian coordinates that are interpreted as spherical coordinates that are then converted to Cartesian coordinates. It sounds complex, but it was easy to write.

Here is a demo:

https://codepen.io/boytchev/full/yLGpaox

image

3 Likes
10

I see it as a deformed cube. Set its vertices with spherical coords :thinking:

Ah! @PavelBoytchev already made a demo with the same idea :slight_smile:

1 Like
11

I’m sorry!

12

wow - thank you so much!!

13

Why so? :slight_smile:
I’m happy, that a solution is already found, when I come to party :smiley: :handshake:

2 Likes
14

yes, use some csg lib. like three-bvh-csg

15

ah yiss, this is indeed simpler way out