Attached Link: Poser Displacement Map Tutorial

Displacement mapping in Poser does NOT alter the mesh (yes I know it says it does in the reference manual but it really doesn’t). Displacement mapping creates the illusion that the surface of the mesh is being displaced. This is accomplished by redrawing the highlights and shadows every time the camera moves and by drawing the pixels of a flat surface in a different location based on the values of the displacement map. Sound complex? Well maybe programming this would be complex but understanding it and implementing it isn’t.

could you post the tutoral anywhere else? rendo is the worst place for it due to the 'pages' rubbish.

Sorry I wrote this tutorial to support Rendo.

It looks interesting.  Thanks for the tute, will probably get something out of it.

I hope so :)

Terrific tute - thank you.

Love the sets in your shop, beautifully detailed and versatile. You should have much success with them.

Cheers!

I hope so! Thanks for the compliments.

o.k., thx fr excellent tutorial, luke. in poser, default displacement causes the renderer to shift the apparent position of the posersurface in the positive normal direction (out), depending on displacement value.  two questions:

• what is yer avatar?  it reminds me of the lion from "wizard of oz"
• is it too late to add a page on the node needed to make displacement shift the posersurface both in-n-out?

It does alter the mesh. I don't understand why you say it doesn't.

It is not just  matter of shifting the normals - that is bump mapping. Displacement mapping actually moves the mesh.

What gave you the idea that it doesn't move the surface?

Left is displacement, right is bump.

The displacement is real. Even the shadow is affected.

There is both positive and negative displacement here. Observe where the red line goes above or below the black line.

The transparency you see indicates where the original geometry position was.

Observe the red line is below the black line on the lower left. That's a graph of the displacement amount - all below the black line means all negative displacement.

YOUR CRAZY! :) LOL :)

I wrote a book on it and looked at the code and talked to the lead programmer at SmithMicro before I wrote the tute. Show me all the examples you want it is not moving the mesh. It is telling the pixels to draw in a different location on the screen hence the term pixel shader vs vertex shader.

It would be impossible to make one polygon distort in such a fashion - that is pixel displacement.

LukeA

btw you are the shader master, no doubt. I would love to learn from you, but I did research that a good bit.

Luke

You looked at the code? You talked to a lead programmer? Which programmer? What did he say exactly?

At least one SM "lead programmer" caused me to end up in a huge argument with some know-it-all in the Daz forums. Mr. KnowItAll claimed that a "lead programmer" at SM said that Poser 7 has always had gamma correction in it, and that my results with gamma correcting shaders was a fluke because I didn't really understand what I was doing. Nothing I could say or show to Mr. KnowItAll proved it to him. His mind was closed by the certainty that everybody at SM knows more about this than me. That is not the case. So keep an open mind.

Let's ignore the voluminous documentation on how REYES renderers (such as Firefly) work that says it slices up your mesh polygons into smaller pieces (micro polygons), moves them according to the displacement information, and then renders those micro-polygons into pixels. Let's look at this scientifically.

You said it doesn't really move the mesh, but rather calculates the pixel value as if it were in its original position and then moves it to a new place on the screen.

If that's true, then the pixel would be lit according to where it originally was in the mesh, correct? It would not be possible for a shadow to fall on the part that appears to be displaced, because the pixel color has already been calculated in some other position, according to what you're saying. Nor could the displaced surface itself cast a shadow, because according to your statement, the mesh is where it always was, and the rendered pixel is what is being moved.

So how do you explain this image?

The white sphere has a displacement, creating a lobe that sticks out. It casts a shadow. Above the lobe, the red sphere casts a shadow on it.

If the mesh was not moved, then all the white sphere parts would be lit as if they were in their original positions, and would only cast shadows from their original positions.

If you think you'll explain it away by saying that the pixels cast and receive shadows, that's not going to fly. It is the mesh parts, the micro polygons, that are moved. The terms "pixel" and "polygon" are not interchangeable.

lol.
 

My big sphere is now made of glass. There are two small decorated spheres. The lower one is being refracted through the glass of the displaced lobe. How is that possible if it isn't really there? How do you explain why the two smaller balls do not appear identical, if the lobe isn't really there between the camera and the little sphere?

If the renderer was just moving the glass pixels to the right, we wouldn't see the sphere through it because in that case it isn't really behind the glass.

This is not an illusion as you described it.

Ok my bad - I think of displacement mapping like in Max where you can only displace the polygons you have created in the scene and this does work that way (slices things up into micro-polygons). I swear I talked to a guy at SM who explained to me it wasn't really displacing the mesh. I did call and got someone named Ken Ho I was told was a lead but I can't find his name anywhere in the credits.

I can change the tutorial with no effect on the content.

LukeA

OK OK :) you are right! :) I conceded defeat.

Yeah the tutorial was good. I just can't have you teaching people that displacement is an illusion, because then I'd have to explain everything 10 times over.

LOL all fixed sir ;)

So now I have a question about displacement mapping. It doesn't break the mesh into individual polys it actually cuts it into a polygon per pixel but they are still connected, right? And the stretching we see when there is a sharp edge and dramatic height difference is one poly being stretched and the texture with it?

Quote - Here's another experiment, which makes no sense unless the mesh has moved.

My big sphere is now made of glass. There are two small decorated spheres. The lower one is being refracted through the glass of the displaced lobe. How is that possible if it isn't really there? How do you explain why the two smaller balls do not appear identical, if the lobe isn't really there between the camera and the little sphere?

If the renderer was just moving the glass pixels to the right, we wouldn't see the sphere through it because in that case it isn't really behind the glass.

This is not an illusion as you described it.

I think Luke meant that displacement doesn't permanently move the mesh (in a way a magnet or a morph brush would).

In 3DS Max and few other high end programs there is Shader based Displacement, like what you get in Poser. Then there's also displacement based modifiers that can be used in mesh modeling. Those actually do change the mesh, in a way a magnet or a morph would in Poser.

Quote - > Quote - Here's another experiment, which makes no sense unless the mesh has moved.

My big sphere is now made of glass. There are two small decorated spheres. The lower one is being refracted through the glass of the displaced lobe. How is that possible if it isn't really there? How do you explain why the two smaller balls do not appear identical, if the lobe isn't really there between the camera and the little sphere?

If the renderer was just moving the glass pixels to the right, we wouldn't see the sphere through it because in that case it isn't really behind the glass.

This is not an illusion as you described it.

I think Luke meant that displacement doesn't permanently move the mesh (in a way a magnet or a morph brush would).

In 3DS Max and few other high end programs there is Shader based Displacement, like what you get in Poser. Then there's also displacement based modifiers that can be used in mesh modeling. Those actually do change the mesh, in a way a magnet or a morph would in Poser.

yes. this is also in blender. you import a black and white image and you can change the whole model with the ''displ'' map. its in real time. it changed the mesh. it will not have details but it will change it. 

Quote - I think Luke meant that displacement doesn't permanently move the mesh (in a way a magnet or a morph brush would).

In 3DS Max and few other high end programs there is Shader based Displacement, like what you get in Poser. Then there's also displacement based modifiers that can be used in mesh modeling. Those actually do change the mesh, in a way a magnet or a morph would in Poser.

 
Why would you think Luke meant that?

He never talked about permanence, nor did I.

He already acknowledged that his explanation of how it works was incorrect, because he was talking about moving the pixels, not the polygons, and called it an illusion. The polygons actually move. Yes, only during the render, and only if you enable displacement in render settings, but they do move during the render.

A magnet, morph or displacement do the same thing. Sure at different times during the process, and using a different control mechanism, but the magnet or morph isn't permanent either.

I understand other apps can deform a mesh at modeling time, not just render time. Be that as it may, his opening statement had nothing to do with 3DS Max. He said:

"Displacement mapping in Poser does NOT alter the mesh (yes I know it says it does in the reference manual but it really doesn’t). Displacement mapping creates the illusion that the surface of the mesh is being displaced. "

Things can work differently in other apps, but the Poser manual is correct and the claim that the manual is wrong is bogus. The claim that displacement mapping creates the illusion that the surface of the mesh is being displaced is incorrect. It's not an illusion, it moves. It's illogical to interpret those words as having something to do with permanence.

In casual conversation with follow up we can be fuzzy about what we say, and clarify. But we can't start a tutorial with a blatant falsehood, regardless of whether or not there are ways to stretch the interpretation to sort-of be meaningful.

Also, if Poser were able to evaluate displacement fast enough, you'd actually see it in preview as well as at modeling/posing time. The only reason you don't is because it would be very slow. The magnet and morph techniques can be done at posing time because they are fast. If displacement were fast, Poser would also do it at posing time. That would be consistent with the other recent improvements in posing time preview, such as the real-time rendering of some more material effects with hardware acceleration.

As soon as hardware can do displacement in real time, they'll add it.

Quote - > Quote - > Quote - Here's another experiment, which makes no sense unless the mesh has moved.

My big sphere is now made of glass. There are two small decorated spheres. The lower one is being refracted through the glass of the displaced lobe. How is that possible if it isn't really there? How do you explain why the two smaller balls do not appear identical, if the lobe isn't really there between the camera and the little sphere?

If the renderer was just moving the glass pixels to the right, we wouldn't see the sphere through it because in that case it isn't really behind the glass.

This is not an illusion as you described it.

I think Luke meant that displacement doesn't permanently move the mesh (in a way a magnet or a morph brush would).

In 3DS Max and few other high end programs there is Shader based Displacement, like what you get in Poser. Then there's also displacement based modifiers that can be used in mesh modeling. Those actually do change the mesh, in a way a magnet or a morph would in Poser.

yes. this is also in blender. you import a black and white image and you can change the whole model with the ''displ'' map. its in real time. it changed the mesh. it will not have details but it will change it. 

Exactly! And it can be exported as a morph target, or stored as 'hard' data - meaning the vertex xyz information, rather then stored as displacement values in an image, and only available during rendering.

If one really wants to split hairs, it can be argues at whih point the 'illusion' starts. Some high lama people will succesfully argue that illusion starts when you hit 'Render' button. Others will have different views.

What bothers me the most about what happened here is that Luke was trying to do something really nice, and got reamed out like he was doing something really bad. :rolleyes:  As if there's a hard consensus on how to define displacement.

Heck, Poser only gives you half the displacement abilities most other applications do. I'd hardly see it as the authority on displacement definition, or much of other 3D stuff. That's probably why displacement is so hard to grasp within poserdom, you only get to see half of it's functionality.

Some people really do need to peek outside the poser box on occasion. I think educating people into thinking Poser is the authority on 3D only does them disservice. Many of those people get burned when trying to participate in other 3D communities (and a large number of Poser users do), and exhibit this attitude elsewhere.

IRRC, within max, you can also tessalate the mesh to refine it for displacement effect.
It's been a little while since I used that functionality, so I could be remembering it wrong. In the past I used displacement quite often to create terrain models - which had to be edited later, to add different thigns to them, like roads, bridges, building pads and various changes. I often work across several applications to accomplish something, so I could be remembering this functionality from another ap... I'm at least 50% sure it's in Max too.

you are wrong.
Luke still did a nice thing. BB just corrected him what was wrong. now he changed it and its all perfect.

p.s. i didnt know that you can do more with the displacement in other software.

I love you all! Lets' end this thread here :)

Ummm. Wow. I didn't ream Luke. You want ream? You have no idea.

Before you get too worried about poor Luke, you should know that he and I began this exchange with a few PM's back and forth before we posted in this thread much. It began with an agreement to stay civil and I'm pretty sure we did. At the top of this page, he shouted he condeded only because we were cross posting. It looks like I was beating him up, but I was just posting a long series of examples of how things work and he responded in the middle. I did not continue to ream him - I was posting.

Anything I talked about here is not Poser bigotry. You can't start a thread that begins with saying the Poser manual is wrong, and expect me to let that go because, what, some other apps we're not talking about do things differently?

Wow.

Seriously let's let this go. bagginsbill and I can come across the same way in electronic communication, I understand him.

Now back to rendering or texturing or modeling or whatever it is you do

:)

Wonderful tute, thanks for sharing! :)

That's a great tutorial. Simple and effective techniques, great results first time.
Yay, I'm a texturer!
(Okay, I have some way to go yet, but at least my stone floor looks like a stone floor).
Thank you!

Quote - could you post the tutoral anywhere else? rendo is the worst place for it due to the 'pages' rubbish.

You could always select the printer-friendly version... all in one page, then.

Excellent tutorial, Luke. Learned as much from it as I did from BagginsBill's addendums...

Thanks everyone! I learned a lot from Bagginsbill too.

Luke thanks for the tutorial it is really appreciated - and I know many people really appreciate the hard work you put into it, and thanks bagginsbill for helping out, your explanations really help gain a deeper understanding of what is going on in the internals.

After all the wrinkles get ironed out, apparently the Tutorial has crashed. :(

*"MySQL error: Table './renderosity/tutorial_tutorial' is marked as crashed and should be repaired, occured in query: "SELECT * FROM tutorial_tutorial WHERE tutorial_id = 2295;".

• LMK

And i get the message: "It seems this tutorial no longer exists".

(But it does exist - I have a PDF version of it!)

bummmer! but I sorta memorised it already.  maybe luke can add the "subtract node" step to the next one.