View Full Version : Major Bump Map differences between LW & Kray

01-05-2012, 02:38 AM
Am a little confused on the surfacing that I was working on for the Xmass Ornament (Globe), in that on the Cap, I was not seeing the results either in VPR nor the Renders at all. LW Version 10.1..

To me the surface was just looking slightly scratched.

Installed the Kray Rendere 2.4 for LW, and gave a simple test with Med to High settings, and it was another world. I understand there will be differences with the render, and GI and such, but for the appearances of the surfacing like that, I am just somehow confused.

Are these differences just due to difference between the two, or is LW doing something wrong (ok, me, not LW).

Pics attached

01-05-2012, 02:55 AM
I have just starting looking into Kray as well.

So not a Kray expert but here is something that might help:



Since Kray uses physically accurate computation to render the scene there are some guidelines that you should try to follow when setting up your surfaces.

Light and material models used in 3d packages (such as LightWave) are not always physically correct. For example in LightWave you can create materials that have diffuse 100% and reflection 100%. Diffuse + reflection = 200% and that means the material reflects (it reflects all light diffusely and reflectively) more light than it receives. Physical incorrectness in a non-GI scene helps to hide lack of global illumination, but in a GI scene such surfaces can look very unnatural.

Kray does not force user to use physically correct models. They are sometimes useful to make rendered images look more dramatic, it is important to know when the scene matches the laws of physics and what will happened if we break them.

The general balance rule that should be followed to avoid unrealistic materials is :


or a more complex version including transparency would be:

Color*Diffuse(100%-Transparency)+Transparency+Reflection+Translucency < 100%

Notice that it is "less than" not "less or equal than". In reality no material reflects all the light that hits its surface. The same rule is valid if we use gradients or textures for every gradient angle and texture pixel.

Balance rule does not affect Luminosity. Feel free to use 300% Luminosity and 95% Diffuse for example.

There were also some settings I read about that could effect bump maps. Can't remember off hand where it was. But have a look through the manual.

01-05-2012, 04:21 AM
I don't see major "differences in bump map", instead I see LW doesn't have reflections at all in top surface..
You should attach scene, if you want us to play with it and find solution.

Are you using non-linear color space? Ball is also brighter than in Kray.

01-05-2012, 11:53 AM
If you're using Radiosity, do you have "Use Bumps" set? This could affect the render.

01-05-2012, 12:43 PM
Ok, uping the scene. Have tried with Use Bumps on and off, did not seem to make any differences, also tried the various Radiosity types..

Also upping a shot of the CS Settings. Am using Jovian as a Color Picker with the Gamma off for in and out, and sRGB for Color Picker in the CS Setting.

01-05-2012, 12:57 PM
Globe_Top has reflection texture - not picked up image.. also scale is insane - 342.49 meters in X?! Y and Z similar >300 meters

01-05-2012, 01:43 PM
Hmnn, will have to check scale, as normally build to life scale unless logos or such to 1 mtr. If the scale is that, I would have to been on some sort of drugs when I built it..... ;-) will re-check.

01-05-2012, 01:52 PM
Ahh, if you are refering to the Image Scale is cm not meters.....

01-05-2012, 02:36 PM
Just add a reflection node to your surface.

01-06-2012, 12:02 PM
Great! Thanks for the insight. Getting there now.

01-06-2012, 12:54 PM
For the LW render, just switch the Reflection Options (Environment tab) to [Ray Tracing + Backdrop].

Currently, it's set up as [Ray Tracing + Spherical Map] so it doesn't see the Backdrop image you're using.

01-06-2012, 12:57 PM
Ahh, that was my main problem then. Thought it was set as you stated, but forgot to re-check it. Thanks.