Level of Detail is an often overlooked factor of CET's performance. While it is great for a seamless user experience, it can be forgotten by developers.
To explain LOD simply, every 3D model placed in the drawing area is represented by a lot of triangles.
Models with a lower triangle count are amazing for performance, but you wouldn't want to use this for a good rendering.
Models with a high triangle count can use up performance, but look amazing in renders.
To get the best of both worlds, CET assigns 4 models of differing triangle counts as 4 Level of Details: Low, Medium, High, and Super in each component.
From top left to bottom right : Low (red), Medium (green), High (blue), Super (yellow).
CET automatically switches between a model's LOD based on a combination these factors:
- Distance from the camera. (if nothing is selected)
- The selected component, and its surrounding components.
- If it's in real-time, or render (selection does not matter in render).
- The computer's available resources.
Here is an example of 3,200 teapot models in CET in real-time:
Here is how this would look like in render:
Though CET switches the LOD automatically, developers are still free to label a high triangle count model as a low LOD label, potentially having CET take a bit of a performance hit, trusting the developer's choice.
We also strongly recommend testing and adjusting models to be within the recommended amount of triangles by referring to these articles:
- Using the QA Tools extension to test components in a drawing, with their 4 LOD models within the triangle budget.
- Using Model Lab to adjust 3D model files to have 4 LODs in CET automatically.
- Under the Validations tab in Catalogue Creator, we can check a catalogue for overly high triangle models with the Mesh data validation.
- For developers to troubleshoot, and adjust the code regarding LODs.