Viewing very detailed models (>1M polygons) on the HoloLens can limit CPU / GPU resources available for tracking and reduce hologram precision. In almost all cases highly detailed models are not necessary for construction and manufacturing tasks, and application performance can be significantly improved by simply eliminating details that are extraneous to the task at hand. Avoid showing details that will not be visible, remove textures from materials and work with simple model formats (boxes, curves and linework) where possible.
Reducing detail for outline rendering
One of the most effective ways to assemble and set out 3D geometry such as timber and steel profiles or pipework connections is to work from outlines. The physical part can be positioned and oriented by placing it within the outlined virtual geometry. However, rendering models as outlines on the HoloLens is computationally expensive and for optimal results the detail of models (and in particular the number of mesh faces in the model) should be kept to an absolute minimum. As a rule of thumb, keep the number of faces in a model to under 100K to maintain 60fps performance.
Default mesh settings for parametric and NURBS pipework geometry may produce high resolution meshes that are unnecessary for mixed reality and lead to compromised performance. When exporting curved geometry such as pipework work with centerlines alone if possible, and when 3D models are required, take care to minimize meshing parameters to produce as little geometry as possible. For instance, a NURBS model of pipework may export to a mesh with 300K vertices by default, while 10K is sufficient to perform layout, QA and visualization.