How to change camera projection to othographic/orthogonal?

[agGitHub]

Hi,

The projection is a perspective projection. I wonder how to change the camera projection to othographic/orthogonal.

Thanks for your help.

[ThomasGorisse]

Hi,
Please use the discussion section for this.
What's your goal exactly for using orthographic projection?

[agGitHub]

I need this feature in order to be able to have clean views when I have a 3D reconstruction of a flat/house/home. For example, if I have a room seen from the top, I want to see only the floor, I don't want to see the walls because of the perspective effect. Thanks a lot.

[agGitHub]

Hi. Any update on this topic? Would be really great to have a camera with orthogonal projection. See for example the three.js OrthoraphicCamera object: https://threejs.org/docs/#api/en/cameras/OrthographicCamera

Would be really great to have the same in Sceneform or a trick to make the camera orthographic. Thanks.

[ThomasGorisse]

Hi,
Could you please ask directly on the Filament repo and link the issue here?

[ThomasGorisse]

Answer here: google/filament#4948

[agGitHub]

It doesn't answer the question. Indeed, I see a setProjection method in the filament version of the objet Camera, but I don't see an equivalent in the Sceneform version of the Camera objet. How to set the projection to orthogonal in Sceneform? Thanks.

[grassydragon]

There is a method for setting the matrix data, however, you may need to use reflection to access it: https://github.com/SceneView/sceneform-android/blob/master/core/src/main/java/com/google/ar/sceneform/Camera.java#L358

Sceneform doesn't support the orthogonal projection explicitly because in AR the camera projection matrix must match the device camera parameters (be perspective and have the same fields of view).

[agGitHub]

There is a method for setting the matrix data, however, you may need to use reflection to access it: https://github.com/SceneView/sceneform-android/blob/master/core/src/main/java/com/google/ar/sceneform/Camera.java#L358

Thanks. I never used the concept of reflection, and I don't know what to set in setProjectionMatrix(Matrix matrix) as you recommend. May you give more details?

Note that I use Sceneform alone in a 3D viewer, not in AR.

Thanks for your help.

[ThomasGorisse]

If you are on a 3D only (no AR usage), try this:

sceneView.getRenderer().getCamera().setProjection(Camera.Projection.ORTHO, double left, double right, double bottom, double top, double near, double far);

[agGitHub]

Thanks for your answer.

I do :

camera = scene.getCamera(); // Note that it is a Sceneform Camera object, not a Filament Camera.
camera.setSelectable(false);
camera.setFarClipPlane(100f);

double near = camera.getNearClipPlane();
double far = camera.getFarClipPlane();
sceneView.getRenderer().getCamera().setProjection(com.google.android.filament.Camera.Projection.ORTHO, -1, 1, -1, 1, near, far); // Note that we use here a filament Camera object ; does it have effect on my Sceneform Camera ?

But it doesn't seem to work as it changes nothing to the 3D view.

Any idea ?

Thanks for your help.

[ThomasGorisse]

Sorry about that, I forgot that the camera projection is updated each frame also outside of an AR usage here:

sceneform-android/core/src/main/java/com/google/ar/sceneform/rendering/Renderer.java

Lines 321 to 332 in 65d6e6e

	if (cameraProvider != null) {
	final float[] projectionMatrixData = cameraProvider.getProjectionMatrix().data;
	for (int i = 0; i < 16; ++i) {
	cameraProjectionMatrix[i] = projectionMatrixData[i];
	}
	camera.setModelMatrix(cameraProvider.getWorldModelMatrix().data);
	camera.setCustomProjection(
	cameraProjectionMatrix,
	cameraProvider.getNearClipPlane(),
	cameraProvider.getFarClipPlane());

So in your case, your setProjection() call is bypassed by the renderer setCustomProjection() repeated call.
That's something we will care about in sceneview-android but if you are using sceneform-android, your only solution might be to call sceneView.getRenderer().getCamera().setProjection(com.google.android.filament.Camera.Projection.ORTHO, -1, 1, -1, 1, near, far); inside the onUpdate() which is called every frame (not the cleanest way obviously)

[agGitHub]

Thanks. I just tried to execute the code at each frame. Tried at the beginning or and of the onUpdate() loop but changes nothing unfortunately. Any clue how to solve this problem ? Thanks.