02-21-2019, 02:46 PM
The problem here is probably that the bounding box of the bigger object is closer to the camera then the individual plane objects and this then leads to invalid order of objects.
For such easy scenarios I would recommend that you do not use the TransparencySorter but manually sort the objects. Just define a ModelVisual3D for the transparent planes and make it the last in the Viewport3D.Children. Then put the planes into that ModelVisual3D. If you also want that the planes are correctly visible through other planes, then you can also easily sort the planes inside that ModelVisual3D - just calculate the distance from the plane to the camera's position (call camera.GetCameraPosition) and sort by that distance.
For such easy scenarios I would recommend that you do not use the TransparencySorter but manually sort the objects. Just define a ModelVisual3D for the transparent planes and make it the last in the Viewport3D.Children. Then put the planes into that ModelVisual3D. If you also want that the planes are correctly visible through other planes, then you can also easily sort the planes inside that ModelVisual3D - just calculate the distance from the plane to the camera's position (call camera.GetCameraPosition) and sort by that distance.
Andrej Benedik