I have a Perspective Camera with a certain projection matrix ,I just want to extract the fow , near plane and far plane from it. I know there is a function in Three.js :

.updateProjectionMatrix()

it creates a projection matrix based on parameters listed above, basically i want the reverse process.

I have a Perspective Camera with a certain projection matrix ,I just want to extract the fow , near plane and far plane from it. I know there is a function in Three.js :

.updateProjectionMatrix()

it creates a projection matrix based on parameters listed above, basically i want the reverse process.

• javascript
• three.js
• projection-matrix

• 1 jsantell./3d-projection – ScieCode Commented Jun 3, 2019 at 14:30
• 1 Possible duplicate: stackoverflow./questions/46182845/… – WestLangley Commented Jun 3, 2019 at 14:45
• From what I read he does not say how to calculate the near and far plane @WestLangley – binaryRat Commented Jun 3, 2019 at 15:10

1 Answer 1

I solved with this 3 formulas :

fov = 2 * atan(1/camera.projectionMatrix.elements[5]) * 180 / PI;

near = camera.projectionMatrix.elements[14] / (camera.projectionMatrix.elements[10] - 1.0);

far = camera.projectionMatrix.elements[14] / (camera.projectionMatrix.elements[10] + 1.0);

Sources :

3D Projection

Depose the OpenGL projection matrix

Field of view + Aspect Ratio + View Matrix from Projection Matrix