The following known issues may or may not be solved in the near future.
The program might freeze or even crash when the number of tracks/objects/triangles to render exceeds your system's (mainly graphics card's) capacity.
Unfortunately the program is not able to predict that before it happens. To reduce chances of its happening:
* Use plain lines as render type for tracks unless you have to use other types, such as tubes, which requires much more system resource.
* Avoid opening multiple windows if you can.
* Delete unwanted objects (track groups and ROIs). Hiding them will not release the resource they occupy.
* Turn off "Force Render" option. "Force Render" may make parameter adjustment more responsive but also will force a lot intermediate rendering.
* Save the scene every time you make important changes to avoid losing your work.
* Do not run other intensive cpu/graphics consuming processes while using this program.
The render engine has problem rendering non-opaque/semi-transparent objects.
Rendering may not look as expected with semi-transparent objects.