I have been trying to model a solid state lidar using the RTX Lidar of Isaac-Sim. I read the documentation here.
What I am trying to do:
- Trying to model a solid state lidar which
- scans row-by-row starting from below
- has no time-offset between channels of the same row
- Let’s say the pointcloud dimensions are (columns,rows)=(100,50) and I scan 100 points at once (bottom row) and these emitters move up a row and scan the next row and this repeats 50 times for one complete scan.
- Lidar frequency is 10 Hz meaning I should receive 10 complete scans per second.
Anyways, I have a few doubts about the documentation.
- For my use case, which is recommended?
- One emitter state with 5000 points in which fireTimeNs list changes its value at every 100th element
- 50 emitter states with each emitter state representinǵ a row
- What is the difference between reportRateBaseHz and scanRateBaseHz which would lead me to the next questions
- What is the difference between firing pattern and full firing cycle in the documentation? (in my case, which is one row and which is one complete scan)
- I assume scanRatesHz is a list of configurable scanning frequencies. How does it help in the simulation if we have to change the actual frequency values ourselves?
- What does ‘tick’ in relation to scans mean; is it per row or per complete scan?
- I understand that the RTX lidar renders frames with a texture which is then post-processed to generate the pointcloud - which of the above frequencies correspond to this frequency of rendering frames?
- What is the purpose of waveLengthNm, minReflectance, minReflectanceRange because I wrote a simple MDL file with spectral properties (defining reflectance values for a set of wavelengths) and I see no effect. For eg., I set the waveLengthNm in the config file to 885 nm and created a material which reflects only light of wavelength=520nm and another material which reflects only light of wavelength=885nm and I saw no difference in the pointcloud (I expected that the rays won’t reflect and hence no points of intersection for the first material)
- What is intensityMappingType which I don’t see in the documentation but the console says that it is missing.
- I also read from one of the forum posts that there are solid-state specific parameters like numLines and numRaysPerLine which are not yet included in the documentation; these parameters are more intuitive but how do we use this to write emitterStates