rendering

Rendering Cheatsheet

Multiplexer: peform long-running task on a remote machine
Filename Manipulation: batch edit filenames
Post-processing: after obtaining rendering file
- Convert EXR to PNG: with Mitsuba renderer utilities
- Image Manipulation: resize, crop, append
Video: convert PNG sequence to video
Storage: check storage status and file sizes
Renew RenderMan: renew RenderMan on Ubuntu
Start Maya: start Maya from command line
Basic PxrSurface: basic shader in RenderMan RIB file

Multiplexer

Use $ screen to keep command running in background
- Create a session
```
screen
```
- List all sessions
```
screen -ls
```
- Return to a session
```
screen -r <session-#>
```
- Exit current session
```
Ctrl + A + D
```
  Filename Manipulation
Add prefix in batch
```
ls | xargs -I {} mv {} <prefix>{}
```
Add suffix in batch

ls | xargs -I {} mv {} {}<suffix>

Remove prefix (for PNG files)
```
for f in *.png; do mv "$f" "${f#<prefix>}"; done;
```
Post-processing

Convert EXR to PNG
Source mitsuba configuration file
```
source /path/to/mitsuba/setpath.sh
```
Convert EXR sequence files to PNG format

Note: source the setpath.sh file if $mtsutil command does not exist.

mtsutil tonemap -t *.exr

Windows

FOR /R %a IN (*.exr) DO convert "%~a" "%~dpna.png"

Image Manipulation

Resize file, <target-width> x <target-height>

convert input.png -resize 1280x1024 resize.png

Resize file, with <target-height> only

convert input.png -resize x1024 resize.png

Resize (or scale) file by scaling percentage

convert input.png -resize 50% half_input.png

Crop file, <target-width> x <target-height> + <left> + <top>
```
convert input.png -crop 1280x1024+10+10 output.png
```

Append file without gap horizontally and vertically

convert col_1.png col_2.png +append output.png

convert row_1.png row_2.png -append output.png

Append file with gap of n pixels horizontally and vertically

convert col_1.png col_2.png +smush n output.png

convert row_1.png row_2.png -smush n col.png

Video

Convert PNG sequence to MP4 with framerate of 24

ffmpeg -framerate 24 -i %04d.png -c:v libx264 -profile:v high -crf 20 -pix_fmt yuv420p output.mp4

Set starting frame to be 10

ffmpeg -framerate 24 -start_number 10 -i %04d.png -c:v libx264 -profile:v high -crf 20 -pix_fmt yuv420p output.mp4

Windows

C:\ffmpeg\bin\ffmpeg.exe -framerate 24 -i %04d.png -c:v libx264 -profile:v high -crf 20 -pix_fmt yuv420p output.mp4

Extract frames from a video

ffmpeg -i output.mp4 frames.%04d.png -hide_banner

Crop a video

ffmpeg -i input.mp4 -filter:v “crop=1920:1080:0:0” output.mp4

Screencast, screen recording of whole screen on Ubuntu
```
Ctrl + Alt + Shift + R
```

Storage

Check total usage of disk
```
df -h --total
```
Check size of directory
```
du -hs /path/to/directory
```
Sort current directory with size
```
du -hs * | sort -h
```
Find a file
```
find /path/to/find -name <filename>
```

Find a directory

find /path/to/find -name <directory-name> -type d

Delete all EXR files
```
find . -name '*.exr' -delete
```

Renew RenderMan

Render RIB file with RenderMan
```
prman -progress <file>.rib
```

To view more details

prman -progress -loglevel 4 <file>.rib

Check RenderMan version
```
prman --version
```
Renew RenderMan license on Linux

Note: will get license with the latest available version

sudo /opt/pixar/RenderManProServer-<version>/bin/LicenseApp

Start Maya

May be shortened
```
/usr/autodesk/maya2020/bin/maya
```

Basic PxrSurface

in RIB (RenderMan file)

AttributeBegin
  Bxdf "PxrSurface" "shader_name" "float diffuseGain" [1] "color diffuseColor" [1.0 1.0 1.0] "string __materialid" ["shader_name_SG"]
AttributeEnd

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rendering

Rendering Cheatsheet

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