Substrate

Replies to This Discussion

Permalink Reply by Emma Chris on July 28, 2013 at 5:04am

Did you find the answer to this question? 

Permalink Reply by David Rutten on July 28, 2013 at 5:16am

What "custom points"? A substrate diagram is a progressional algorithm. Every new line segments is constrained by all existing line segments. What sort of control do you want over the output?

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David Rutten

david@mcneel.com

Tirol, Austria

Permalink Reply by Emma Chris on July 28, 2013 at 6:23am

Well, I was looking at how Voronoi works with attraction points and I was wondering if there is any component that might work with rectangles in a similar way. 

Can you explain better the logic behind the construction of subsequent lines in substrate component? Thank you!

I guess the two topics are separate at this point. 

Permalink Reply by David Rutten on July 28, 2013 at 10:16am

Substrate works as follows:

1. A boundary rectangle is constructed.
2. A random point somewhere within this rectangle is picked.
3. A random direction is picked.
4. A line is drawn from the point in the positive and negative direction until it hits a boundary edge.
5. A random point on the new line is picked.
6. A line is drawn from that point, perpendicular to the base line until it hits a boundary edge or a line already part of the Substrate diagram.
7. Repeat steps 5 & 6 until the desired number of lines is reached.

There are some details regarding angles and the like, but they are not very important. The whole algorithm can be condensed to:

Pick a random point on any line already part of the diagram.

Draw a new line starting at that point until you hit another line.

Repeat.

There are some things that could be added to this algorithm, though it would require changing the source code or writing a new one from scratch. For example you could make the random-point-on-existing-line logic non-random. Perhaps the odds are greater that a point will be picked in some areas rather than others. This would allow for some control of density.

Another modification could be that several lines are generated one of which will be elected as the true line for that iteration. This would allow one to filter segments to achieve specific lengths or a specific length distribution.

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David Rutten

david@mcneel.com

Tirol, Austria

Permalink Reply by Emma Chris on July 28, 2013 at 3:02pm

Thank you! Very clear explanation!

Permalink Reply by Fred Becquelin on July 28, 2013 at 7:06am

Wouldn't that be OcTree?

Permalink Reply by Emma Chris on July 28, 2013 at 3:08pm

I was looking at OcTree as well as QuadTree and noticed that they work with grids. I was looking for something irregular/random.

In any case, I got to know what OcTree is. I will study it better.