adding displacement cancels other displacements

[TheBadger]

On my temple model, I used a B/W image map to create initial displacement. I then added procedural displacement to the model. I expected that the one would be added to the other, but instead the first is completely gone do to the second.

I thought that where there was no procedural displacement that the image map displacement would remain, but it doesn't.

What can I do to keep both the way I intended?

Here is the node as an example:
[attach=1]

In this case the function is connected to a series of nodes that create the displacement you see in this image http://www.planetside.co.uk/forums/index.php?action=dlattach;topic=20292.0;attach=58751;image

Note the flat smooth areas that appear to have no texture. This is texture there if I remove the other displacements. Is there away to get the complex displacement to not hide the other? For example in PS, I would alter blending modes and this way get the layer beneath to show through. How can I do something similar in TG?

@fleetwood
If you are seeing this, can you explore this issue? Not sure how to approach editing your nodes if this is the only way.

Thank you.

[Dune]

I am under the impression that this should work, so additive. Strange. If all fails, you can bring in the displacement map in a separate image map shader, then merge with procedural (through transform). With a lot of the same (kind of) objects using the same map this is handy anyway, as you can relay that image map shader (or combi) to all 'instances' or copies of that object.  Saves memory.

[TheBadger]

If you have a moment, ulco. can you build a tree to screen grab? You don't need to make it work, just show how you know it can work. IF that makes sense?

[Dune]

Just about to leave, but you're just in time  Have to dash now 

Here's what I mean; you can take either, added after the default shader with extra displacement (disabled, as you don't need both), or into the displacement tab. Hope this makes sense. Merge can also be controlled by PF's (through transform), but isn't necessary.

Image map shader set to UV!

[TheBadger]

cool, thanks!

[fleetwood]

I tried this with your columns and found that it all depends on how much black is in the particular displacement image you are using.

It seems that any additional displacement  function will only show up where the displacement image happens to be  white, but not where the image is black.

So it may be that your displacement image has a lot of black meaning the function portion contributes nothing in the black areas.
I would suggest inverting the displacement image in an editor and trying it out. Maybe your displacement image needs to be built on 50% gray instead of black.
Maybe a multiply operation is going on instead of an add, so black is zeroing out things.

[Dune]

Multiply may well be the case. Matt will know for sure.

[Matt]

The displacement function and the displacement image are multiplied together, to be consistent with how all the other kinds of images and functions behave in the rest of the shader (and because it's sometimes useful). If you want to add displacement, use another displacement shader after the Default Shader (or before, that will work too).

Matt

[TheBadger]

Thanks all!

The next and last question on this topic is the offset. I don't know if I am getting results because of the OP issue, and that offset results will be clearer when I fix the OP issue per the ways in this thread. Or if I just don't understand it, period. At first after reading the wiki on it I thought it may be a way to force negative displacement by first being positive, which is to say I thought somehow offset raised up and then sucked in surface, sorta like a crater dose in appearance, when using negative values in the offset.

In the context of this thread, having seen the temple model, and the other related threads, how do you explain the displacement offset?

[Dune]

I also tried displacing everything out, except where you need inward displacement, but that is not ideal.

[Matt]

Hi Badger,

I'm afraid I don't understand the question.

Matt

[TheBadger]

Sorry, not sure how to ask since I don't get what the function does in a model context.

Perhaps you can just imagine some model that it may be useful for, and I can just gain understanding of it from your example. But since you did not understand my question, then I think the wiki on that is confusing, since that is what made me think the way I did, and which I can't explain

[bobbystahr]

Sorry, not sure how to ask since I don't get what the function does in a model context.

Perhaps you can just imagine some model that it may be useful for, and I can just gain understanding of it from your example. But since you did not understand my question, then I think the wiki on that is confusing, since that is what made me think the way I did, and which I can't explain

I don't think, or didn't think you could do anything to an imported model except bump mapping, no displacement....has this changed or is it a paid feature?

[Oshyan]

Displacement Offset is just that - an offset. It adds or subtracts (depending on positive or negative) a fixed, uniform amount to the displacement. So for example if you had a terrain that was exactly as you wanted it (i.e. the amplitude, distance between peak and valley, of the terrain shapes was good), but you wanted it to be raised 100 meters up (keeping the exact same shapes), you'd add a 100m positive offset. How this interacts with objects I'm not certain, except to say that as you know object displacement is a bit finicky.

If I understand your thought process correctly, you are maybe thinking that if you displace outward by 1m, then use a displacement function/map to add *negative* (inward) displacement of -1m *or less* (i.e. it does not displace *below* the original surface), then perhaps it will avoid the artifacts you're seeing. I honestly do not know if that is the case, but it should be easy enough to try. Matt, assuming my understanding is correct, does my explanation of the idea make any more sense to you?

- Oshyan

[TheBadger]

You get me Oshyan  

Well, I thought from the beginning, that what I was trying to do was a messy hack. But sometimes in TG you get pretty good results if you don't push things to far, when using nodes not as they were meant.

Thanks for the clarification on the setting. IT makes more sense to me in general now.

I don't think, or didn't think you could do anything to an imported model except bump mapping, no displacement

You can displace the shit out of anything, Bobby. Just can't promise you it will look good. Just turn RTO OFF! Works pretty good for most things. Surprised you missed all the threads on this subject?