If you are experiencing issues with frame rates, synchronization times or disappearing geometry on the HoloLens you may want to consider setting up your Rhino scene for optimal performance in mixed reality. This includes customized meshing of NURBs geometry, decimating mesh geometry, checking geometry normals and materials.
Fologram for Rhino uses Rhino's default meshing pipeline to stream geometry to the HoloLens. If you have very large or detailed polysurfaces this may result in significant latency issues. To get around this you can use the Mesh command to create a mesh from your NURBs geometry with customized parameters such as maximum edge length or aspect ratio.
You can reduce the file size of large meshes by 'decimating' the mesh into fewer polygons. Polygon count will significantly affect performance especially when animating geometry in Grasshopper. Use the Fologram Decimation component or the Rhino ReduceMesh command to reduce the polygon count of your mesh to a specified number or percentage.
Modelling in Rhino often involves working with NURBs surfaces without any thickness. Fologram for HoloLens uses one sided materials to optimize rendering performance, and the 'back faces' of these surfaces will appear transparent in mixed reality. Use the Flip command in rhino to invert the direction of your surface, or use the OffsetSrf or MeshOffset commands in Rhino to thicken these objects. Keep in mind that thickening produces more geometry and so will affect latency and frame rates on your headset.
Avoid using black materials as while they will preview correctly in Rhino, these will display as transparent on the HoloLens (an absence of any light in the HoloLens display) in mixed reality. Remember the HoloLens can only add to light entering your eyes - it cannot take it away!