I am trying to visualize a Janus particle using Sphere-Surface-Glyph in ParaView. My goal is to create a hemisphere/sphere glyph whose symmetry axis is aligned with the Z-axis. I noticed that ParaView Glyph orientation assumes the default orientation of the source geometry along the X-axis (as also mentioned in previous discussions). Therefore, my custom hemisphere glyph was initially oriented with its symmetry axis along X.
To make the glyph physically match my particle coordinate system, I applied a Transform filter and rotated the glyph source by 90 degrees around the Y-axis, so that the polar axis became aligned with Z.
The geometry orientation is now correct, and the Glyph Orientation vector works as expected. However, I encounter an unexpected issue with lighting: when the particle rotates, the shading/highlight pattern changes as if the light is rotating together with the object. Even when I use a fixed light source (Scene/Headlight), the illumination appearance changes with the glyph rotation.
My understanding is that the Transform rotates the geometry and therefore also rotates the surface normals used for lighting calculations. And I could confirm this by skipping Transformation, and getting expected lighting. I would like to let the glyph rotate without affecting the apparent illumination. Is there a recommended workflow for this?
Thank you!