Expander improvements

Expander is one of the most important nodes for manipulating shapes. I feel like it can be improved further and open the door for more shape design possibilities.

I’d love to see these Filter Types which exist in Gaea:

  • Disk (circular 12 sided)
  • Diamond (45 degrees rotated square)
  • Cross
  • Oct (circular 8 sided)
  • Corner (this one is similar to Diamond)
  • Ring (circular 6 sided)
  • Sobel (I think this expands in a single direction)

Would it also be possible to add a heightfield for controling the radius of expansion?


I miss these from Gaea also.

This definitely sounds interesting as a feature, I haven’t used Gaea much myself but I think this will help open up more possibilities in World Machine.

Those sound great!

Btw, you can already create an octagonal expasion with the Thermal Weathering device. If you use the WM2.x version, set the Strength to 1, Massbalance to 1 and Rock Angle to 0, you get the desired effect, albeit a bit fuzzy. This will create a “max” effect. With the Massbalance set to 0, it will create a “min” effect.


Hi there,

I agree - the Expander is a really powerful device, and I want to continue making it more so! I like the idea presented here.

Can you explain more about how you’d like to use the Expander? Are you using it to change landform shapes, massage selection areas, etc?

The only problem with implementing more shapes is that most of the above are not separable filters - what that means essentially is they are very computationally inefficient to evaluate with large sizes. A straightforward evaluation with a kernel size larger than a dozen pixels or so can get quite slow. In some cases you can decompose a non-seperable filter into a sequence of separable ones, but have not investigated this yet.

For your last question, I believe this should be possible as-is!

Thanks for your reply. Yes I am using it to change the shape of certain areas. Sometimes I use it to inflate certain areas to add more mass and make it more rock like. I don’t plan on using it with large radii, because the shapes won’t look natural when you overdo it.

Regarding the reply to my last question. Did you mean you can already control the radius per pixel on the expander with a heightfield or did you mean it should be possible to add this feature? If it’s already possible, how can one do this?

@HYLK: Thanks for the cool trick!


As long as the radii is kept small, adding additional useful shapes would be pretty straightforward… Maybe with some kind of notice about the performance implications to prevent unexpected results :stuck_out_tongue:

The radius per pixel isn’t possible right now unfortunately. but what I meant is that it should be a relatively straightforward add.

1 Like