bump mapping in difusse material

[cjd2]

Exactly Vinz , I wanted to get to the point that I decided to start this post .
I searched the entire forum, and whenever the topic was touched on a "light", I found a convincing example of bump for a diffuse material.
Then I said:
"Here there is a problem."
And after a week of waiting an example that shows that Octane is entirely possible to make this effect, there is no solution, there is only one problem.
Thanks for your opinion Vinz.
Regards
Cjd2

[radiance]

Exactly Vinz , I wanted to get to the point that I decided to start this post .
I searched the entire forum, and whenever the topic was touched on a "light", I found a convincing example of bump for a diffuse material.
Then I said:
"Here there is a problem."
And after a week of waiting an example that shows that Octane is entirely possible to make this effect, there is no solution, there is only one problem.
Thanks for your opinion Vinz.
Regards
Cjd2

Hey,

I did multiple diffuse materials with bump mapps on the lamborghini model.
they definately work.

There's always a reason to why it's not working and i'll figure it out tomorrow at work,
and report here.

Radiance

[vinz]

hey radiance, my opinion is that bump working pretty nice for a lot of things, but i've to admit that i'm not able to do a convincing brick wall with bump as in all renderers that i've used ... it's not a real problem for me, i think we only spot this as a stuff to improve.

or probably it is my mistake, btw nobody here has shown us a good brick walls made with bump map.

[radiance]

hey radiance, my opinion is that bump working pretty nice for a lot of things, but i've to admit that i'm not able to do a convincing brick wall with bump as in all renderers that i've used ... it's not a real problem for me, i think we only spot this as a stuff to improve.

or probably it is my mistake, btw nobody here has show us a good brick walls made with bump map.

it's usually due to the fact that the scene scale is not correct to the bump scale.
if it's way too large, you don't see bumps.
if it's way too slow you don't see the bumps as you see only one small part of one huge bump.

Radiance

[n1k]

The thing is that you can not make convincing brick wall using only bump or normal map regardless of rendering engine. It may work for distance shots but as soon U get closer it's going to be bad. Bricks are too big pieces of details to be made with only bump map IMHO.

Cheers,
n1k

[cjd2]

Thank you , thank you all for making their contribution in this area .
Radiance Thanks for waiting .
Well, it is likely that the error is doing it myself, but I can not cope .
I ask then, help to clarify this issue.
Please, when you have solved the cube with textures such as brick, teach us how we achieve this effect .
Thanks and greetings to all.
Cjd2

[cjd2]

Radiance , do you have some example? .
Thank .
Cjd2

[radiance]

Hi,

I don't understand what you want.
Diffuse bump maps works fine just like any other bump maps.

The only thing you need to realise is that if you have a diffuse material in a diffuse environment (eg an environment light source) you won't see much or maybe no bump mapping at all as there is nothing to change the bump map angle against while viewing.

To see the relief of a bump map, you need a directional light source and or a directional BRDF, like specular or glossy, not diffuse.

The example you give me of yafaray and BI i cannot replicate as octane at this point does not have area lights so i can't set up a directional lightsource.
i can use the sunsky enrivonment.

anyways, since this is such a heavily dicussed topic i'm inclined to waste the afternoon making images...

Radiance

[radiance]

Hi,

Examine the images.
As you'll see diffuse does support bump, but since it's a omnidirectional material (eg it scatters light in all directions),
adding a bump mapping to it (eg offsetting the new ray direction) does'nt make much influence as it's an hemispherical material, eg it scatters in all directions.

diffuse with no bump:

diffuse with bump:

That's it, also realise that this cube is large, so that's 2 meters wide.
since there's approx 4 bricks per side that's one brick = half a meter.
I limit the bump depth, otherwise new users won't set the value to a very small one (eg one milimeter or less) and they will have a lot of artifacts and complain,
as bump mapping is not displacement mapping and can't be used to add a large amount of relief, only a tiny bit.

on a glossy material it's much better as this material is directional, eg it gives a glossy 'highlight',
which accentuates the bump maps used.

Glossy with no bump:

Glossy with bump:

So just take care to import correct scales (this will be very important for the future material db system anyways),
and use bump maps to create fine detail and bake displacement for large eg > ~5 milimeter displacements.

Also, the image you used has a low resolution, and it's in most areas clamped to black and white, eg there's no real different between (eg greys),
which causes the bump map calculation to not be able to compute the direction vector accurately.
I'm sure if you take a propper bricks image map from a pro texture CD and it's bump map you'll get a much better result.

Radiance

Radiance

[vinz]

radiance don't be upset but for me this brick wall is not convincing at all, the yafaray and blenders renders that cjd2 posted in this this topic are far away more interesting in term of bump. and cjd2 used the same map as these ones...

i think it means the bump map of octanes should be used only for small details... is it kind of octane bump limitation ?