Scene Perception demo R200 (C++) .obj format

[Finfa811]

Hello,

I would like to know the format of the .obj files that are saved using the Scene Perception demo R200 (C++). Is it?:

v x y z r g b

being x y z in meters, and r g b in normalized values from [0,1]?

Is it a right-hand system: x+ right, y+ down, z+ to the world, with the first camera pose as reference?

Thanks.

[Finfa811]

Any help, please? Why the output format is not a standard .obj file, like for example the one extracted from the 3D Scan (C#) demo?:

v x y z

vt u v

vn nx ny nz

[Félix_D_]

Hi there,

This was posted a long time ago, but yeah, you got it right, its :

v x y z r g b

With distances in meters and normalized color values in [0, 1].

The right-hand system you gave is also correct, and the reference is the first camera pose from the color point of view, with a strange small pixel-wise decay in my case (+21px, -6px). This might be due to camera intrinsics correction. Plus, if you use a device with IMU, by default the gravity support will be set to true and the reference will be different. I think the reference from the first pose is rotated in order to have gravity directed along the y+ axis (down), for better reconstruction of planar surfaces parallel to the ground.

[Finfa811]

Hi Felix,

Thank you for providing a detailed answer, I should have done it when I solved my question.

You are right in everything, I have built a device with IMU + r200 and I realized the same issue. You can play with EnableInertialSensorSupport and EnableGravitySensorSupport to find a good solution for IMU cases. Besides, coordinate system can be changed as well using the flags in pxcsession.h:

        COORDINATE_SYSTEM_REAR_DEFAULT = 0x100, /* Right-hand system: X right, Y up, Z to the user */
        COORDINATE_SYSTEM_REAR_OPENCV = 0x200, /* Right-hand system: X right, Y down, Z to the world */
        COORDINATE_SYSTEM_FRONT_DEFAULT = 0x001, /* Left-hand system: X left, Y up, Z to the user */

Cheers.