CERES Ray Tracer (CRT) Demos

This repository contains some demo files for the CERES Ray Tracer. Install that first (either from source, or directly for PyPI) before running any of these.

The python API allows for both "static" and "dynamic" scenes.

• Dynamic: The BVH is constructed from scratch every time a frame needs to be rendered. This increases the total rendering time however it allows you to modify each loaded 3d geometry in-between frame renderings.
• Static: The BVH is constructed once allowing for faster overall render times. The downside is that none of the geometries can be modified.

Cornell Box with Render Passes:

python cornell_box.py

This script will produce 4 images in a new sub directory named output_cornell_box:

• render.png: The rendered image
• depth.png: A pass containing the distance to each ray intersection
• instance.png: A pass where each color indicates a different object
• normals.png: A pass where each pixel is colored by the normal vector of the intersected point

ROSETTA Mission Animation

This script requires flight data from the ROSETTA mission available from the Planetary Data System Navigation Node for ROSETTA. This is not a tutorial on how to use SPICE, so if you are unfamiliar, simply make sure to download all of the required files below. If you're on a system that can run bash scripts, you can download this data by simply running:

cd kernels/
./get_kernels.sh

If you cannot run a bash script on your system (for example, if you are on Windows without WSL), you must manually download the following SPICE kernels:

Link to File	Description	Location to put it
CATT_DV_257_03_______00344.BC	Attitude kernel (CK) for Comet 67P	spice_kernels/ck/
ROS_SC_REC_160101_160601_V01.BC	Attitude kernel (CK) for ROSETTA	spice_kernels/ck/
ROS_CHURYUMOV_V01.TF	Frames kernel (FK) for Comet 67P	spice_kernels/fk/
ROS_V37.TF	Frames kernel (FK) for ROSETTA	spice_kernels/fk/
NAIF0011.TLS	Leap seconds kernel (LSK)	spice_kernels/lsk/
ROS_160929_STEP.TSC	Spacecraft Clock kernel (SCLK)	spice_kernels/sclk/
RORB_DV_257_02_______00344.BSP	Ephemeris kernel (SPK) for ROSETTA	kernels/spk/
CORB_DV_257_02_______00344.BSP	Ephemeris kernel (SPK) for Comet 67P	kernels/spk/

Once all files are downloaded and placed into the correct file structure, this script can be run using:

python comet67p.py

This script will render a sequence of images between 2016 MAR 2 12:00:00 and 2016 MAR 4 12:00:00 from the perspective of the ROSETTA spacecraft in orbit around Comet 67P/Churyumov–Gerasimenko. These images will be saved to a new directory named output_comet67p/ with a naming convention of frame_xxx.png. It will also shows how to perform batch lidar processing:

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Contact

All questions, comments, and concerns should be directed to Chris Gnam: crgnam@buffalo.edu