Renderers

A renderer calculates the final picture from a 3D scene: how light bounces, how glass bends it, how shadows fall. Animux has seven, from very easy to research-grade.

Which one should I use?#

All seven side by side, with full names and what each does best: Renderer comparison.

Beginners: use Cycles, explained in Blender and the first-render tutorial.

Try every renderer in two minutes#

Each renderer has a sample scene in /usr/share/animux/samples. The self-test renders all of them and saves the pictures in ~/animux-selftest/<date>/:

animux-selftest povray blender mitsuba luxcore appleseed pbrt gaffer

These are the pictures the self-test made on Animux (in a virtual machine, a few seconds each):

POV-Ray#

POV-Ray reads a text file that describes the scene, and writes a picture.

#include "colors.inc"
camera { location <0, 2, -6> look_at <0, 1, 0> }
light_source { <-5, 10, -10> color White }
plane { y, 0 pigment { checker Gray White } }
sphere { <0, 1, 0>, 1 pigment { color Red } finish { phong 0.8 reflection 0.2 } }

Save that as ball.pov, then either choose 3D Animation → Renderers → POV-Ray and pick the file (the picture opens by itself and is saved in ~/Pictures/povray/), or type:

povray +Iball.pov +Oball.png +W1280 +H720 +A -D

+A turns on anti-aliasing (smooth edges), -D renders without a preview window. Hundreds of example scenes are in /usr/share/povray-3.7/scenes.

LuxCoreRender#

LuxCore is used here as a Python module in Animux's ready-made Python, animux-vfx-python:

animux-vfx-python /usr/share/animux/samples/luxcore/render.py ~/luxcore.png

Read render.py to see how a scene is described (camera, materials, lights) and how long it renders (a time or quality limit). LuxCore's Blender add-on (BlendLuxCore) is not included in r16.

Mitsuba 3#

mitsuba scene.xml -o out.exr
animux-vfx-python /usr/share/animux/samples/mitsuba/render.py ~/mitsuba.exr

Mitsuba writes EXR images; view them with DJV or convert them: oiiotool ~/mitsuba.exr -o ~/mitsuba.png. Mitsuba 3 can render in RGB or spectral mode, and can compute how the picture changes when the scene changes (for research and machine learning). Documentation: https://mitsuba.readthedocs.io/.

appleseed#

Only the command-line renderer is included (the appleseed.studio editor needs Python 2.7, which Debian 12 no longer has). The menu entry asks for a .appleseed project, renders it and shows the result.

appleseed.cli "/opt/animux/appleseed/examples/cpp/helloworld/reference output/test.appleseed" --output ~/appleseed.png

pbrt-v4#

The renderer from the free online book Physically Based Rendering (https://pbr-book.org/). The book explains every line of its source code.

cd /usr/share/animux/samples/pbrt
pbrt --spp 64 --outfile ~/pbrt.exr animux-spheres.pbrt
imgtool convert ~/pbrt.exr ~/pbrt.png

--spp sets the samples per pixel (quality). The Animux build runs on the processor only. Large example scenes: https://github.com/mmp/pbrt-v4-scenes.

Gaffer + Cycles#

Gaffer can also render with Cycles from a node graph, the way lighting artists work in studios.

Render times, roughly#

A 2-minute film at 24 frames per second has 2,880 frames. Several minutes per frame quickly means days. Test with small resolution and few samples, and use a render farm or render overnight.