Hello
Inside an Action node, in a 3d space with some geos and camera projection workflow, for a reason for some geos, certain frames, when I draw a Gmask, I can see the vertices but the lines are non visible, and of course the mask is not cutting off the geo as it suppose to be.
It is a camera that pan 180 around an object, nothing fancy, I thought it is a clipping issue
Any ideas?
Best
after a small research and checking the mask in 3d space, when I create it, for some reason it is drawn in the camera plane, means almost touching the center of the camera. The workaround was to draw it from top view, but then, it has this annoying constraints with the camera view, making moving points in logical directions impossible … any one has an idea how to break the constraint with the camera ? I mean, this is a mask which is linked to a geometry not to camera, no ?
From my understanding, gmasks are always drawn through the result camera. This catches me up all the time when I do a camera track then go to draw a 3d shape to project onto, before switching my result cam. So that’s the first step. Make sure you’re actually looking through the correct camera.
Even so you can still end up with the problem you’re having. For me this most often happens when I’m trying to use a point locator to situate a 3d shape using plane transform in the axis behavior. Essentially the axis rotated is in such a way that when the transformation data is applied to the gmask, as you put points down through the result camera, the gmask will be placed in 3d space in a way that is incoherent through the viewer.
To combat this you can use a Look At link that will force the axis to orient itself towards the object it is linked to. That way when you place a gmask parented to the axis the mask will be placed along the same plane. If you’re just trying to use the gmask as an occluder for a separate piece of geo then you should be able to place an axis as the child of your geo’s axis then use a Look At link to connect that axis to your camera and then, with the axis selected, pull out a gmask from the node bin and start placing points. This should place the object at the correct location is Z and force it to always be oriented to camera.
I only started using the Look At link recently so I’m still familiarizing myself with exactly how it works, but I think this should help resolve your issue.
Thanks my dear, that was clear enough 
I will try to familiarise myself with the look-at link