Specifications about the number of polygons and LOD

[GiannisChalkias]

Could you please provide some guidance on what's the best way to ask manufacturers for the ideal 3D Files to provide all 3 LOD models for a fixture? I would like to have an easy explanation to a CAD engineer so that he can immediately translate the LOD in the table below:

The model currently does not have any children.

All models of a device combined should not exceed a maximum vertices count of 1200 for the default mesh level of detail.

There are three level of details that you can define:

Table 33. Mesh level of detail

LOD	Description	Folder 3DS / gltf
Low	Optional; This is the mesh for fixtures that are far away from the camera. It should have 30% of the the vertexes from the default mesh vertex count.	3ds_low / gltf_low
Default	This is the default mesh that is used for real time visualization in preprogramming tool. It should have the minimum vertex count possible, while still looking like the fixture in 3D.	3ds / gltf
High	Optional; This is high quality mesh targeting non-realtime applications, where the vertex count is not that important. There is no limit for the vertex count.	3ds_high / gltf_high

Low and High meshes definitions are optional. Place the file with the same name in the defined folder.

Sending this table was not always accepted without further questions. For example, the polygon count is also asked back.

 

[Petr Vanek - Robe]

Hello Giannis,

we describe the "quality" or "size" of the 3D asset by using vertex count, this being in the Spec and also in the Builder. It is a value commonly seen in 3D software like Blender. I am not sure what a "polygon" would be meaning here - would that be a triangle?

As for the level of detail:

One can use the provided GDTF Primitives of base, yoke, head, triangle, sphere... these have been created to be as simple as possible, when no other 3D asses is available.

The "default" level has been chosen to be 1200 vertices for the complete fixture. A complete fixture "typically" being a moving head and this has been providing good guidance in our experience, as it makes people aware of the properties of 3D models. So for base/yoke/head fixture, this ends up being some 400 vertices per model. If the fixture has many lenses, these would typically be referenced, but when preparing our 3D assets, if we have a way to test in real software, we look at what the fixture looks like and ensure good first hand experience.

The low level of detail allows to provide even simpler models with more decimation, i am not sure if any software is using this at the moment.

The high level of detail is there to allow unlimited details to be expressed.

Kind regards

Petr