I do not know if this is a bug, or a default characteristic of procedurally generated Selenas; but all of them have these golden-orange-brown "patches" or "strains" in large parts of their surface.
I tried changing their colour both directly from the script, and through a palette. The colours of the Selena change accordingly; but the golden stains remain.
I took several screenshots from random procedural selenas, in which these "patches" can be seen.


What is the cause of this?
Thank you in advance.

Selenas are more or less the equivalent of our Moon, so those patches would be the the equivalents of "Maria", flattened basins originated by crust activity, which melted the rocky mantel, caused perhaps by major impacts or something similar.
Pretty standard in all selenas.

Selenas are more or less the equivalent of our Moon, so those patches would be the the equivalents of "Maria", flattened basins originated by crust activity, which melted the rocky mantel, caused perhaps by major impacts or something similar.
Pretty standard in all selenas.

If those blotches are supposed to be maria, they definitely need to be improved. First of all, maria have well defined edges; these are just sort of subtly there. Second of all, the terrain doesn't change. Like you said, maria are flattened basins, but in SE, they have the exact same terrain as any other part of the selena. The only thing that tells you it's maria is the orange hue. Lastly, is it just me, or is orange not the way to go for maria? In real life, maria is dark, not bright orange. Overall, I feel that they're just repetitive and ugly. (I'm not mad, I'm just a scientist who wants accuracy.)

If those blotches are supposed to be maria, they definitely need to be improved. First of all, maria have well defined edges; these are just sort of subtly there. Second of all, the terrain doesn't change. Like you said, maria are flattened basins, but in SE, they have the exact same terrain as any other part of the selena. The only thing that tells you it's maria is the orange hue. Lastly, is it just me, or is orange not the way to go for maria? In real life, maria is dark, not bright orange. Overall, I feel that they're just repetitive and ugly. (I'm not mad, I'm just a scientist who wants accuracy.)

Seconded.

I have tried blanking out the Palette information on Selenas but it seems no matter what changes I make that gold color will not go away.  I also had this problem with my Interstellar addon, this has lead me to think this is caused from something in the shaders.

I will put in some time experimenting with the shaders but if it is in tg_common that will be a pain to edit.

I have tried blanking out the Palette information on Selenas but it seems no matter what changes I make that gold color will not go away.  I also had this problem with my Interstellar addon, this has lead me to think this is caused from something in the shaders.

I will put in some time experimenting with the shaders but if it is in tg_common that will be a pain to edit.

Thanks a lot for your time.

I've also tried changing the surface parameters, looking for a cause. Removing the marias does nothing.
The only parameter that affects the orange stains is Randomize, which only displaces them.

If those blotches are supposed to be maria

Actually, it appears I'm wrong. There are two parameters affecting the presence of smaller impact basins on selenas (mareFreq, mareDensity), but they change only surface structures not color, which I suppose it would change mostly according terrain composition.
I would go then for radioactive wastelands

I'm just guessing here, but perhaps those yellow stains are meant to resemble sulfuric Io surface?

I'm just guessing here, but perhaps those yellow stains are meant to resemble sulfuric Io surface?

Then they would probably only be in large objects, or objects experiencing large tidal forces.

Then they would probably only be in large objects, or objects experiencing large tidal forces.

Good point. But I still think that it's the most plausible explanation. The color scheme for the stains is just too similar with that of sulfur deposits (black, red, orange, yellow). Maybe there are other means for them to appear?

Also, keep in mind that Io is classified as "selena" in the game, so it actually makes sense that some of its features might be used as basis for procedural selenas.

If I remember correctly, SpaceEngineer implemented randomized browning for some worlds in a recent-ish version of SE, although I forget which. Might this be the result of that?

If I remember correctly, SpaceEngineer implemented randomized browning for some worlds in a recent-ish version of SE, although I forget which. Might this be the result of that?

Of course it is, what we're discussing here is if those brownings are scientifically-correct from an aesthetic point of view.