[Ernesto]

Hello you all

I am trying to create a water material, and am having problems with the bump map.
The material that I am creating is in real measurements, meaning that the tile size is constant, although i am testing diferent bump maps.
I have noted that 256x256 pixels maps that represents 4 meters by 4 meters in the water surface, results in smooth surfaces with smooth reflections.
On the other hand 4096x4096 pixels bump maps that represents the same size on the water surface, looks pixelated or draw strange curve lines as if the water waves were made of flat steps at diferent levels.
I am a bit disoriented here.

I was expecting the oposite behaviour
Am I right ? is this a bug?

Are there any general considerations on bump maps that I have missed?


Ernesto

[michaelplogue]

It would help if you could post some renderings and your settings. can't really judge anything otherwise....

[fuso]

I had good results with this one. If it's too pixelated you might want to
give it a Gaussian blur of 1.5 or something in Photoshop. Good luck mate.

[Ernesto]

Here you are:
The expected reflections and refractions are close to image 003, but they aren't smooth, but pixelated.
Decreasing resolution makes them more pixelated.
Increasing resolution shows smaller pixels but cannot find the way to make them softer.








No matter the bump map resolution all the reflections and refractions are pixelated, but as soon as you increase resolution of bump map, its behaviour gets weird.
E

[NicoR44]

Hi Ernesto,
Could you share a part of your pool with the water surface in a pack and go file, to see what's going on?

[Ernesto]

Here you are
www.4dempire.com/Scene.zip

[NicoR44]

checking

[Ernesto]

[NicoR44]

hehe, I mean, I'm running some tests right now

[NicoR44]

Hi Ernesto,

This is what I have so far, I've been playing with tilling and bump a bit.
I will upload the material later on today.

[Ernesto]

Thanks For your Help Nico!
Anyway, I was trying a diferent effect, which seemed impossible to me: A quiet swiming pool.
Your samples shows a water material that looks more like a sea seen from an helicopter. In other words the waves are very small compared to a human being. Or it could looks like hot water boiling at 100 Cº.
I was trying to see very smooth waves about 50cm wavelength and perhaps 3 or 4 cm height.
The expected reflections are close to the 3rd sample I posted, but instead of deconstructed reflections, I was expecting continuous curved reflections.
In your last sample, where the waves are bigger, the reflected and refracted lines are starting to broke into pieces. Anyway those waves needs to be scaled up several times, for the pool scale.

Ernesto

[Ernesto]

Nico,

This image has been rendered with another software.
Look at the smooth curve lines resulting from refractions and reflections of the straight lines in the bottom of the pool and the wall behind the human figure.




Then look at these 3 details:





Where you could see the diferences:
The first image was rendered with another software, but shows the desired effect. Look at the continuity of the joints that look curved by the refractions and reflections.
In Maxwell Render all the reflected and refracted lines that should look curve, are defragmented, as shown in 2nd detal image, all joints look broken. In case of increasing resolution of Bump Map there will appear more artifacts as shown in the 3rd detail. The result is similar to a flat plane with steps, instead of a continuous curved plane.

Ernesto

[Ernesto]

In my oppinion this is a bug in the bump behaviour.
I miss any procedural tool to solve this instead of using a bump map.

Ernesto

Here You have real photos:

[NicoR44]

Ah, I think that the reason is that the water is a single surface and does not have any volume.
I'll do some further tests tonight and use a bigger wave to get the right effect

[Ernesto]

It seems that the bump effect is independent for each pixel, and Maxwell is not considering that there should be continuity between pixels.
In this way we can only reproduce a fragmented apearance.
When the resolution is small, and each pixel of the bump map represents a bigger sqare on the water surface, we get a less fragmented result, because there are not so much pixels.
On the other hand if we get a high resolution bump map, the result will be a very noisy surface.
But it is not possible to get an aparent continuity in the reflecting surface, as well as in the refracted joints.

Ernesto