## Displaced strata techniques (Was: Hells Bend: a render with shapes done with function nodes)

Started by Volker Harun, January 31, 2007, 10:35:27 am

#### Volker Harun

##### January 31, 2007, 10:35:27 am
Hi Frank,
thanks for giving the tipp with presets coming ,-)
Well, I have played a bit with functions - but did not find anything with slope around - errr - did you use a normal distribution-shader for that one?

For anybody else ... use the normal shaders that you have and make some strata-displacement. Attached is a WIP.

Volker Harun

#### littlecannon

##### February 02, 2007, 07:14:19 pm #1
Quote from: FrankB on January 31, 2007, 05:03:55 am

this is simply an exponential function with a rotating exponent (a sinus)

Hi Frank

I love experimenting, but I have no idea what that actually means.  I hazard a guess that it has something to do with the functions in the node network, but I can't find "an exponential function with a rotating exponent". I can find Exp colour and Exp scalar under Power in the Functions and I can find a Rotate Function... is this what you speak of? I attach a jpeg to make it clear what I'm saying.

Regards, Simon.
I just need to tweak that texture a bit more...

#### old_blaggard

##### February 02, 2007, 07:48:42 pm #2
Look at the parentheses: he says he used a sinus, aka a sine curve.  I don't have TG2 open right now, but I'm guessing that's what he meant.
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#### littlecannon

##### February 03, 2007, 09:54:23 am #3
Quote from: old_blaggard on February 02, 2007, 07:48:42 pm
Look at the parentheses: he says he used a sinus, aka a sine curve.  I don't have TG2 open right now, but I'm guessing that's what he meant.

Yeah, I know what a sine curve is, that's not what I asked. I want to know what an exponential function with a rotating exponent means in plain English not math jargon, and what relates to it it in TG2, i.e. what am I looking for... Functions, a displacement, a type of shader.... Sorry for sounding ignorant, but i don't need to know math algorithms as my work involves design and artworking, not rocket science, so most of my math left me when I left school many years ago. So if anyone can spare the time to explain what this all means, then I'd love to know. A screen shot of what this is, would have cleared this up at the start and maybe hidden the fact that my math isn't that hot.
Regards, Simon.
I just need to tweak that texture a bit more...

#### FrankB

##### February 03, 2007, 11:18:53 am #4
Quote from: littlecannon on February 03, 2007, 09:54:23 am
Quote from: old_blaggard on February 02, 2007, 07:48:42 pm
Look at the parentheses: he says he used a sinus, aka a sine curve.  I don't have TG2 open right now, but I'm guessing that's what he meant.

Yeah, I know what a sine curve is, that's not what I asked. I want to know what an exponential function with a rotating exponent means in plain English not math jargon, and what relates to it it in TG2, i.e. what am I looking for... Functions, a displacement, a type of shader....

Hi Simon,

by rotating exponent, I mean a range of values for the exponent that repeat over and over again. See, when you use an exponent function, e.g. exp(y), it will quite rapidly grow into enormeously high values. So instead of exp(y), I am using exp(sin(y)), which only returns values between 0.36 and 2.7 (the exp function then provides a particular shape for the curve)
Now why am I using this function anyway? The idea started with wanting to create terraces and overhangs based on the altitude of e.g. a canyon wall. So for example, every 10 meters, I want the steep wall to become an overhanging terrace.

If you would like to see how exp(sin(x)) looks like you may want to use this function plotter: http://www.univie.ac.at/future.media/moe/fplotter/fplotter.html

QuoteSorry for sounding ignorant, but i don't need to know math algorithms as my work involves design and artworking, not rocket science, so most of my math left me when I left school many years ago. So if anyone can spare the time to explain what this all means, then I'd love to know. A screen shot of what this is, would have cleared this up at the start and maybe hidden the fact that my math isn't that hot.
Regards, Simon.

It's true, you shouldn't be required to be a math head to work with TG2. But just because functions are available, it doesn't mean they are there for you in particular. I think functions are aimed at individuals which are skilled enough to understand the internals of a renderer, so that they can create new functionality. I myself don't count me in that group, although I understand a wee bit of the math required. But what I do know is that those cool effect created with functions will become easy to use presets in TG2 at a later stage. I think many "regular" shaders available today have been built using functions. To us, those "regular" shaders become easy to work with, but we don't comprehend HOW they actually work internally. So no need to feel bad about that.
Anyway, I don't want to give away the complete setup of this scene so soon. I have committed to providing the scene to Planetside for them to consider a preset based on that, but that's all about what I'm prepared to give for now. Anyway, once it has become a preset, you don't need to worry about the internal functions anymore

Cheers,
Frank

#### Volker Harun

##### February 03, 2007, 01:02:29 pm #5 Last Edit: February 03, 2007, 01:05:31 pm by Voulge
Hi,
attached is a simple file showing displaced strata along one axis.
You can see in the image that at the vertikal view to the axis, the strata looks weird, but interesting.

Guess that Frank's and Oshyan's presets will be more versatile - but for the meantime ...

Volker

Edit: Do not forget to generate the heightfield, to see the effect

#### littlecannon

##### February 03, 2007, 01:22:15 pm #6
Hi Frank, Thanks very much for the explanation and giving away what you could, I'll be tinkering away and finding out what I can... and to Volker, thanks for the tgd, I'm going to give that a look now.
Simon.
I just need to tweak that texture a bit more...

#### BPauba

##### February 03, 2007, 02:43:05 pm #7
Quote from: Voulge on February 03, 2007, 01:02:29 pm
Hi,
attached is a simple file showing displaced strata along one axis.
You can see in the image that at the vertikal view to the axis, the strata looks weird, but interesting.

Guess that Frank's and Oshyan's presets will be more versatile - but for the meantime ...

Volker

Edit: Do not forget to generate the heightfield, to see the effect

Great work man. Very cool

#### FrankB

##### February 03, 2007, 05:36:09 pm #8
Quote from: Voulge on February 03, 2007, 01:02:29 pm
Hi,
attached is a simple file showing displaced strata along one axis.
You can see in the image that at the vertikal view to the axis, the strata looks weird, but interesting.

Guess that Frank's and Oshyan's presets will be more versatile - but for the meantime ...

Volker

Edit: Do not forget to generate the heightfield, to see the effect

Very cool concept, indeed!

#### Mohawk20

##### February 06, 2007, 05:50:57 pm #9
By keeping to Franks hints, I've conjured up this little configuration.
As you might have guessed, it doesn't work (Oh wonder)...

That is mainly because I have yet limited understanding of the alliance and order of nodes.

We have to be able to achieve this. One man could, so we as a team should be too.
Howgh!

#### Tangled-Universe

##### February 14, 2007, 07:56:03 am #10
Looking at Frank's explanation, thanks for that Frank by the way!, I'd say you should reverse the order...well, at least don't start with the exp scalar.
I'd try to start with the y scalar, then the sin and then the exp, or start with sin, then y scalar and then the exp. Haha, this sounds really stupid

I have the most faith in the first option, lol

Martin

#### Ogre

##### March 12, 2007, 12:39:32 pm #11
I was able to generate this effect
"If you find me feeding daisies
please turn my face up to the sky and leave me be watching the moon roll by.
What ever I was it was all because I've been on the town washing the BS down."

-Gordon Lightfoot

#### rcallicotte

##### March 12, 2007, 01:59:26 pm #12
Cool.  It looks like the side of a huge water tank.
So this is Disney World.  Can we live here?

#### Ogre

##### March 12, 2007, 02:28:01 pm #13
Yeah..It was just a circular image displacement

Ran it over lunch on a Strata shader and got this
"If you find me feeding daisies
please turn my face up to the sky and leave me be watching the moon roll by.
What ever I was it was all because I've been on the town washing the BS down."

-Gordon Lightfoot

#### old_blaggard

##### March 12, 2007, 04:46:45 pm #14
Interesting....
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