Trace Image Node #92461

New Issue

Jarrett Johnson · 2021-10-25T04:06:02+02:00

Jarrett Johnson commented

2021-10-25 04:06:02 +02:00

Trace Image Node

This task outlines a design proposal for a Trace Image geometry node.

Similar to Grease Pencil's functionality, the node receives an Image input and generates a Curve geometry.

Resolution: The higher the resolution, the more control points are generated for each spline
Color Threshold: Since potrace requires a black and white image, images are first converted to BW images. RBG values for each pixels are greyscaled and compared against the threshold to determine if the pixel is black or white.

Use cases

There seems to exist many use cases for a Trace Image Node (as stated by several users), and likely even much more, and would be a good node addition for the newly added image socket.

One can generate:

geometry from logos, and other images
complex curve arrangements like circuits
contours and terrains
swappable data to replace downstream curves in node trees to modulate behavior
etc.

There's likely even more possibilities and implications for the nodes including mapping these curves onto a 3D surface.

Implementation

For the most part, the implementation should be straightforward since there's already existing functionality in Blender via potrace used by grease pencil. However, much of the source code that performs this conversion is specific to that module.

Potential Issues

I haven't used Grease Pencil's trace image much, but from initial, miniscule testing with a very complex designed logo, it has some trouble generating a clean trace. However, it does a decent job on simpler logos.

Additional Questions

Grease pencil supports tracing an image sequence. Community members have also inquired support for this in this node. What should be the expected output and behavior?

# Trace Image Node This task outlines a design proposal for a `Trace Image` geometry node. Similar to Grease Pencil's functionality, the node receives an `Image` input and generates a `Curve` geometry. ![TraceImageLayoutV2.png](https://archive.blender.org/developer/F11538407/TraceImageLayoutV2.png) - Resolution: The higher the resolution, the more control points are generated for each spline - Color Threshold: Since potrace requires a black and white image, images are first converted to BW images. RBG values for each pixels are greyscaled and compared against the threshold to determine if the pixel is black or white. ## Use cases There seems to exist many use cases for a `Trace Image` Node (as stated by several users), and likely even much more, and would be a good node addition for the newly added image socket. One can generate: - geometry from logos, and other images - complex curve arrangements like circuits - contours and terrains - swappable data to replace downstream curves in node trees to modulate behavior - etc. There's likely even more possibilities and implications for the nodes including mapping these curves onto a 3D surface. ## Implementation For the most part, the implementation should be straightforward since there's already existing functionality in Blender via [potrace](http://potrace.sourceforge.net/) used by grease pencil. However, much of the source code that performs this conversion is specific to that module. ## Potential Issues I haven't used Grease Pencil's trace image much, but from initial, miniscule testing with a very complex designed logo, it has some trouble generating a clean trace. However, it does a decent job on simpler logos. ## Additional Questions Grease pencil supports tracing an image sequence. Community members have also inquired support for this in this node. What should be the expected output and behavior?

Jarrett Johnson commented

2021-10-25 04:06:02 +02:00

Changed status from 'Needs Triage' to: 'Needs Developer To Reproduce'