View Full Version : Reflection Woes

08-02-2004, 03:17 PM
Can anyone help?

Here's some background info:

I am trying to render a model I built of a software box. The lightwave model is based off of the real box. On the real box, there is a spot UV gloss coating that is highly reflective. Since it is spot, it is not covering the whole box, simply put there are distinct areas of the box where there are high reflections, and areas of the box where there are no reflections.

Onto my reflection woes:

The model I created has a UV mapped color texture. I applied a UV map to the reflection property of the surface which clearly defines the areas that need to reflect the background. I gave the scene an environment to reflect, got all my lights together, etc. etc.

When I render, I do not get the desired effect I am looking for! I realized that the reflection layer is multiplied with the color layer, and therefore can not get an isolated reflection with color underneath.

I am completely stumped on how to get around this. It seems to be a functionality of lightwave that cannot be altered by a preference. Anyone have any pointers?

08-02-2004, 04:27 PM
I am not sure if I am right or not, and I am sure some one will correct me if I am wrong. However I beleive if you load a reflection map as a shader then the base color should be a shade of white. For the type of reflection your looking for try loading the reflection map into the background instead of the shader. Then set your shader to reflect raytace+backdrop. Then you can use a base color.

08-02-2004, 09:59 PM
Any object that is very reflective has very little diffuse. If you want 80% reflectivity, that only leaves 20% diffuse (unless you want to reflect more light than there is hitting the box). So you can't see a lot of reflection and the box label at the same time.

I have a feeling this gloss coating is not reflective when viewed straight on, directly at the box, but it is at an angle. Use a gradient in the reflection channel set to 'incidence angle', 100 at the 90 degrees end and 0 at the 0 degrees end. Put this layer above the UV layer and set the blend to 'Alpha'

Put these 2 layers in the Diffuse channel, but invert them.

08-03-2004, 08:55 AM
Silk rooster - thanks, I looked at the shaders, but I can't find one that I can load a reflection map into.

Your method makes a lot of sense to me. It is less reflective when looked at straight on. My problem is that even when looking at it at aprox. a 45 degree angle, there is no reflection due to the multiplying of the color channel. I will try the gradient with an incidence angle to achieve a fresnel effect. Hopefully that will work...

Thanks for your input!

08-03-2004, 08:35 PM
Sorry about that, I meant the environment tab in the surface editor. There is a place to load a reflection map. Sometimes I use the word shader incorrectly.

08-05-2004, 12:28 PM
Hey guys,

I tried to implement the suggestions that you gave me, but it didn't help unfortunately. I think that the look that I am trying to achieve will have to be done with extra modelling. The look is similar to a photo in a glass frame. You can see the image in the frame, but there is an element of reflection from the glass on top of it. I am guessing that I have to create the gloss coating on the software box by a similar method. Putting a clear transparent, glass like shapes on top where the image shows through from underneath. This is the only thing I can think of, which means a lot of extra work to make this model look right. Oh well...

08-05-2004, 01:57 PM
I'm a complete idiot...

I was ready to give up and move onto build a new model and a friend/co-worker of mine saw that I had something turned on that should not have been. I had color highlights turned up to 100% in the advanced tab. Go figure, I don't remember turning that on. That took all the specularity and reflection and multiplied it to the color layer, which killed my UV effect.

This was a lesson well learned, and I don't count this as a complete loss because I have implemented an incidence angle gradient, which I might not have if I didn't post this question.

Thanks guys for your help... I will post a finished still shot some time tonight...