Shader Question

Roland4

Can someone tell me please what this is ?

Environment Functions --> Terrain Bump

Is there a Tutorial how i can use it ?

thx Roland4

3DAGE

HI Roland4 :)

Most shader functions in carrara can be used in different ways,.

For example:
In a Terrain shader,. you can create different terrain layers, and each layer can be a terrain layer using terrain distribution,.. or a conventional shader like a texture map, or a more complex shader like a Multi-channel shader, which has separate channels for transparency reflection,... and Bump,..

In a Multichannel shader, (within a terrain shader) you could use a "Terrain Bump" in the bump channel,.. which would effect the bump values in this channel of the terrain shader.

You could also make the bump channel into a more complex "Mixer" using the terrain bump and other shader functions.

The Environment functions /Terrain bump ,... is available as a separate function , to allow you to use it on (Non terrain) objects.

for example: by adding a "terrain bump" in the Bump channel of a shader applied to a Sphere, you could create a distant moon or planet.

See pics.

Hope it helps

thoromyr

While tutorials are handy you can learn quite a bit with experimentation. That particular shader element appears to have been introduced in 8 or 8.5 (it isn't included in the documentation I checked). It doesn't have many settings:

Size: this is the resolution to use for the bump map. The smaller the size the finer grained the result.

Shuffle: this is almost certainly intended to change the seed for the generation of the bump map. In my testing it didn't do anything, YMMV

Amplitude: change how deep or shallow the bump map is.

Follow Terrain: presumably adjusts the algorithm to conform with the terrain. If set to zero the bump map is even across the surface, high values lessen the intensity on more nearly horizontal surfaces (e.g., the sides of a hill have strong bump than the top).

Roughness: controls how rough vs smooth the bump map is.

Non-Uniform: this allows the use of a non-regular size. That is, the element making up the bump can be longer than it is wide. This is done by changing the frequency for each rotation axis. That is, lowering the default of 144 on X causes "stretching" around the X axis as there is a smaller number of elements to stretch around it.

Transform tab: this is the same as on other shader elements and allows warping ("transforming") space for how the effect is applied.

[edited because of errors in original composition]

Roland4

Hi 3DAGE

Thanks for the answere. Is the Terrain Bump a static Function which I can not change ?

Example for my question.:

In a normal bump channel i can use anything else like noise, marble, cellular as a bump funktion. In the terrain bump panel, there is nothing to change the bump structur itself.

thx Roland4

thoromyr

thoromyr said:

Follow Terrain: presumably adjusts the algorithm to conform with the terrain. If set to zero the bump map is even across the surface, high values lessen the intensity on more nearly horizontal surfaces (e.g., the sides of a hill have strong bump than the top).

The more I think about it the more I'm inclined that this uses the slope in a slightly different way than implied above. For example, if you apply it to a sphere (as 3dage illustrates it) the effect is definitely lessened at the top of the sphere, but not at the bottom. When applied to a terrain and using a high value for 'follow terrain' it doesn't have much effect along the top of a saddle, but has effect along the sides. IIRC it also didn't have much effect in the bottom of a valley.

With that in mind it would probably be more accurate to say that high values of follow terrain reduce the effect based on slope and proximity to local maxima. Of course, it might be just the slope value depending on how it is calculated -- but regardless it isn't a matter of how level the region is (because it affects the bottom of a sphere strongly even with a high value in 'follow terrain').

thoromyr

Roland4 said:

Hi 3DAGE

Thanks for the answere. Is the Terrain Bump a static Function which I can not change ?

Example for my question.:

In a normal bump channel i can use anything else like noise, marble, cellular as a bump funktion. In the terrain bump panel, there is nothing to change the bump structur itself.

thx Roland4

You can always mix the bump with a noise function. Noise is how I generally create procedural bumping. But at least in terms of altering the terrain's built in generator: you can supply parameters but not change it. It wouldn't make much sense to as the entire point is to expose the terrain functions bump generator. If you want to use a different noise you can.

I haven't tried, but I suspect you could use a different terrain function to get a "number" for the slope which you could then multiply a noise function with to simulate the "Follow Terrain" feature.

3DAGE

Exactly thoromyr :)

all the parameters of the terrain bump should be animatable, but as thoromyr points out you can also make a more complex mixer and control what changes by using the blend channel

Roland4

Thanks all, i will make many experiments to make complex bumps for rocks and so on.

thx Roland4

wetcircuit

Thanks for pointing out this shader. Playing around with it in the bump channel of a simple shader (with Slope to create the snow) applied to a terrain...

wetcircuit

and some renders...

Roland4

Nice, but it is not exact what i mean. Here is an example that shows what i mean. I make it with Blender but i want make it with Carrara.

thx Roland4

wetcircuit

Despite 3DAGE's interesting pic I do not believe this shader is intended to make continents. I believe it is meant for terrains (as are all the Environment shaders).

The best planet-maker I have played with is a photoshop plugin called LunarCell by Flaming Pear:
http://flamingpear.com/lunarcell.html

Enhance:C is a Carrara plugin at Digital Carver's Guild that has some interesting Planet Shaders
http://www.digitalcarversguild.com/plugin.php?ProductId=18&BannerId=13

wetcircuit

Roland4 said:

Nice, but it is not exact what i mean. Here is an example that shows what i mean. I make it with Blender but i want make it with Carrara.

thx Roland4

For an effect like this I would try MULTIPLY or OVERLAY operators with noise and cellular shaders.

Roland4

holly wetcircuit said:

Despite 3DAGE's interesting pic I do not believe this shader is intended to make continents. I believe it is meant for terrains (as are all the Environment shaders).

The best planet-maker I have played with is a photoshop plugin called LunarCell by Flaming Pear:
http://flamingpear.com/lunarcell.html

Enhance:C is a Carrara plugin at Digital Carver's Guild that has some interesting Planet Shaders
http://www.digitalcarversguild.com/plugin.php?ProductId=18&BannerId=13

Thanks for the tips holly wetcircuit, but the problem from me is, that i have no credit card and so i can not by the products via internet.

thx Roland4

3DAGE

HI Roland4 :)

If you create a Mixer in the Bump channel,.. then you can add (bump layer 1) and (Bump layer 2) to the two "source" channels in that mixer,.
then you can add the (mask layer) to the "blender" channel.

so, the final result will be (source one) "bump layer 1" and (Source two) "bump layer 2" mixed together, using the (Blender) "mask layer"

You should also be able to create those images / textures,.. procedurally, using the "fractal noise" functions in Carrara.

quick example, using the colour channel so you can see the Black and white.
hopefully you can see the differences in the little spheres for the fractal noises used in the two sources, and the blender channel.

This Mixer, can be copied and pasted into the bump channel, and most other channels.

Roland4

Thank you very much 3DAGE. This is very good and now "es funzt". I wish Carrara has the Terrain and Materialtools from Bryce.

thx Roland4