vtkOpenGLSphereMapper not working (or perhaps not understood how it works)

So i wanted to make some memory used and time of rendering tests with 3D points, to display them i needed them to be spheres, i first used the glyph3d Filter but it turns out when you go over a million points it takes way too much memory, so i tried the vtkGlyph3D mapper and it was a blast, clearly faster, bu i would love the imposter technique to work on my projet so i can compare the speeds and memory sizes. So i tried giving my point dataset that i gave to the other filters to the mapper, turns out it doesn’t display anything, i tried a lot of things, and it only shows them when i add some 3d geometry before the mapper.
Am I missing something? Or is there no other ways to do so? Anyway thanks for reading and for the help if you provide some!