If you are finding your file being very slow to navigate, slagging on the screen as you move the mouse, and very slow at loading, that is likely because your file is too big. But I have a few tips on how you can optimize your SketchUp file for best viewing experience:
1. Purge all your layers into one. Modelo renders your model by layer, meaning each additional layer will increase the rendering time. The fewer layer for Modelo, the better.
There are free SketchUp plugins that can help you purge and clean up your file. The one I used is called Cleanup3, you can get it at the Extension Warehouse.
2. Clean up your duplicated textures and reduce the texture sizes. We've seen many files have duplicated textures, and each texture gets rendered separately, dramatically increasing the rendering time.
I tied plugins like "Resize Texture" and "Goldilock"
Also, when I upload to Modelo, I check "Reduce texture file size for faster rendering"
3. Don't play with the model while it is still loading. You've probably noticed by now that you can start rotating around in the 3D space while the model is still loading. However the constant changing of camera positions will cause some re-calculation in the background, and thus slowing down the loading time and the rendering time. Resist the urge and don't touch it until its done!