Blender Geometry Nodes Starfield & Motion Lines (Update 3.6)

Starfield + Motion_Lines

Hese are two geometry node setups to scatter stars or lines on a sphere or half-sphere geometry. Both are light, fully procedural (no mesh) and can be transformed and animated in many ways. No simulation here.

I have been using those stars many times for space and sci-fi illustrations. It can be used to achieve FX (like star wars light-speed effect)as well.

It comes with 3 procedural shaders: Stars, Lines, World.

Version:

Blender version is 3.6.4.

This setup version is 1.1. If you had already purchased the previous version, you can upload the new one.

What's new:

- new groups, enhanced presentation and performance.

- geometric culling feature on both. It will delete points outside the camera field.

- control object to ease orientation and scale of motion lines.

How to use it:

There are two collections: Starfield and Motion _lines. They are ready to use, just tweak parameters in the modifier tab. Camera culling needs the right camera values (focal and picture ration) to work properly. You can use a driver when having an animated focal length. 

Note: If you have a slow computer, avoid raising size (or density) too fast to prevent the number of points getting very high. Or set a high Kill_points value (near 1), and then decrease it.

Motion_Lines parameters (Starfield is just a simpler version of it):

Sphere_Radius: size of the emitter surface

Half-Sphere: switch to an half-sphere emitter. 

 point density is relative to the emitter surface so if you raise or shrink it, the number of point will follow.

Seed: emission random value

Kill_points: reduce the number of points randomly. Useful to animate appearance\disappearance effect, or adjuting visible points without changing density.

Line_radius: base Thickness of the lines

Line_Length: base length of the lines

Min_Size: small size will be randomized around this value

Max_Size: large size will be randomized around this value

Magnitude: increase or decrease the gap between the largest and smallest sizes.

Normal_to_Tangent: align instances to emitter surface. 

Align_to_Controler: align lines with the Lines Controler object.

Camera_Culling: Enables camera culling

Camera: pick your active camera

Picture_Ratio: this value (resolution X / resolution Y) is needed for a good computation of camera culling, the method being geometric here (faster than raycast, it ignores ocludded objects though).

Frame_Scale: raise the value above 1 to prevent instances from poping during animations. 

Focal_Length: the length of your focal (default is 50mm). This value is needed for a good computation of camera culling.

Material: material assigned to the line instances. 

License: for any use, personal, educational or commercial.

By Sébastien Garnier / Anabase Studio, May 2024

Contact, feedback, requests: Anabase.studio@gmail.com