Procedural bump turns black

Hey guys, you may have a few suggestions.

I ran into a Blender limitation I guess. I have a huge procedural node tree, and if I add another node someplace on the bump line (even back at the texture part), the whole bump and material turns black. It takes about 5 bumps, or sometimes 6, but the 7th would turn black (or the 6th if I add anything to that texture setup).
I could mix the bump textures, sure, but it would not serve me, since I need to control the bump separately, and I could not mix them properly to do so.
The textures and setup is surely fine, I’ve been working on this since weeks, but I am a bit dishartened now…

As I read, it is not a bug, but a limitation in Blender, however I have seen much much bigger node-trees (I may have ca. 200 all in all lol), but still, it should work IMO:

Any news on this issue since the 2015 post, any workarounds maybe?
Thank you! :slight_smile:

You could add more bumps with math nodes, before you put it into the height of the Bump node.Just connect and mix your bump maps together.

oops overread this.hmmm good luck then

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Check the console if you get an out of stack memory or something like that. I forgot the exact wording but it was something with stack.

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Yes, tried it. In theory, you could control bump on the BW scale but we all know it wont really work. You either see it or not XD cant really smoothen it out with greys :disappointed_relieved:

Thanks, I will check it!

I dont understand this. Grey and hight should be the same data.

Yes, but the bump in my experience is much undercontrolled on the BW scale. If I pick a .250 or .500 gray, it wont be half as bumpy. Should be but wont XD The tweaking is not that smooth.

Plus one bump map will go from 0 to 1, but it means the inbetween stuff is lost, just stuffed in there. What if I want something on top, that also goes from 0 to 1? Over-multiplying would not really work either :confused:
But anyways, if that is the only way, I will try to smoothen it out like that. Stuff everything from black to white, and we will see… 🤷 But the bump controller should be the better option.
Anyways, I will check it out today :blush:

I was interested how the bump works,and here you can see all the maths about.

First from stackexchange

Then the code from the bump node,how its gets mixed.

And Finaly the paper the bump node code is based of.


What a treat :star_struck: thank you, I will definitely check it out!

hmm… but you can have infinite stuff between 0 and 1.

Yeees, kinda, but I want grout and dust on top of tiles. If the tiles go 0 to 1 then where are the rest? Plus, I cannot set the tiles, say 0 to .8, and leave the .8 to 1.0 area for the rest. The difference could not be seen, plus I could not properly mix the colours :pleading_face::pleading_face:
Anyways, I will try to mix not all but 1 2 of these at least

Maaaybe use map range nodes to convert all maps to their designaged range. I will try it later

If you didnt get it working by now, its a little hard to see where the issue is without seeing everything to the left of the mix nodes as well. I am a little dyslexic so getting through all of the posts in the thread is a little tough for me. It looks from your picture like you are saying the last bump node in the chain is causing you problems. Can I see whats plugged into that? Technically there are better ways to handle stacking bump maps but its a little hard to say if that has at all anything to do with it without seeing what all is being connected into what.

Thank you All, the problem was unfortunately the “Cycles: out of SVM stack space” after I checked the console, it was confirmed so I picked that one as solution.

I combined the bump textures with map ranges and mixes, it works now, but it is a bit inelegant for my taste :smiley: anyways, it is a workraround. I find it a bit funny though, why is this a processing limit, when I only use around 100 Mb of memory (hard on the computing part ofc), but even though it is a complicated setup, I have seen much larger ones as well, and a huge scene also takes more to handle, maybe not this way, but you know what I mean. So math nodes seem to be okay if stacked, but it seems Blender doesn’t like texture nodes that much… but still, we need those to do our thing :smiley:

What is also a workaround, is switching to CPU render, and tick in the Open Shading Language, that won’t use this SVM stack thingie, but makes everything obviously slower.

Anyways, I have learnt a lot, thank you guys, have a lovely evening!!