View Full Version : Why didn't anybody tell me LW supported Reflection Blurring?

06-24-2003, 11:17 PM
Heh I feel like a dork. For the longest time, I've been generating spherical images and blurring them in Photoshop for creating blurred reflections, I had no idea that they finally included a 'blurred reeflections' value under the Reflection Environment tab. When'd that happen?

Just venting. I've been wanting this a while. Hopefully Newtek will allow me to assign a texture map to define how blurred a reflection is.

Here's a tip for you all with objects with detailed specularity: Try applying your spec map to the glossiness channel. You'll be surprised how it comes out, especially in an animation. ;)

06-24-2003, 11:22 PM
You should keep doing it the way you are doing it. Blurring reflections in Lightwave is slow.

Triple G
06-24-2003, 11:23 PM
Well, don't feel like too big of a dork. For most things, especially animations, you're still better off faking it with a blurred image map. If you haven't discovered it already, LW takes an eternity to calculate "true" blurred reflections. :hmm:

06-24-2003, 11:23 PM
I haven't really used the blurred reflections.
But maybe it's better to blur them in PS for the sake of rendertimes.:shrug:

Edit: Whoa, that's some fast posting guys :)

Triple G
06-24-2003, 11:23 PM
Hehe....Shade01...too quick on the draw for me today...:wavey:

06-24-2003, 11:55 PM
Originally posted by NanoGator
Why didn't anybody tell me LW supported Reflection Blurring?

You never asked. :curious:

PS - I agree with the others-- it's very slow. Unfortunate, because it can look quite nice.

06-25-2003, 01:32 AM
Blah it does take a long time.

It isn't clear to me why this algorithm would need to take that long to generate a blurred reflection. Well.. hmm... okay, I can kind of see it now.

I'll haveta ponder on that, there's got to be a way to do it quickly!

06-25-2003, 01:46 AM
My theory is that it's probably looking at the original image, looking at the end result based on the percentage, then interpolating and aliasing the image until it's blurred.

06-25-2003, 03:12 AM
The reason why it takes longer is because it is tracing more than one ray per pixel. When you blur increase the blur amount you are widening the cone of rays send out per pixel.

In a hypothetical render 1 ray x 500 pixels vs 12 rays*500 pixels. Imagine if you had two blurred reflective surfaces facing each other. Every time it hits a surface it would spawn another 12 rays.*

**I just picked the number 12. LW docs never published how many rays it sends.

06-25-2003, 03:54 AM
I just blur them in the image editor with fp blur, doesn't seem to make rendertimes longer. It's faster than switching to another app just to blur, and I don't need to keep track of image maps with different levels of blurriness.

Triple G
06-25-2003, 04:01 AM
Originally posted by DaveW
I just blur them in the image editor with fp blur

Ahh...I always forget about that...dunno why. Thanks for the reminder! :beer:

06-25-2003, 05:45 PM
Thanks for the explanation Bob. That's sorta what I thought it was up to. (Strange that it only gives you a percentage controller though...)

06-25-2003, 07:52 PM
No problem, I'm not really sure why they wouldn't want to give a number of rays. I miss that in the volumetrics too. In steamer we could say how many samples, not we can choose low/med/high. What's with that?

06-25-2003, 08:07 PM
Hmm, I think that a jitter would help geting aling with less rays.
You know we used to fake that with microbumps, which are more or less a jitter right?
So I would suggest to NT to have another slider to define the jitter on the rays, in combination with the slider for the amount of rays it should look quite good.
Anyone tried it in combiantion with the soften reflections- image- filter?

06-25-2003, 08:07 PM
Sometimes you can do cool stuff with the built in reflection blurring.... for example...since it is linked to reflection, if you add a Fresnel filter... and you have your reflection planes just right... you can make it look like the further the object is away from the reflective surface, the more blurry it gets. --- Here is a render I did a while ago where I used that trick. (It's a link because it's 1600X1200)... (was a desktop pic) Oh... can anyone recognize the logo? :)

1600X1200 Reflection Blur Pic (

06-25-2003, 10:47 PM
Oh neat!! I've been wanting to recreate that effect! Thanks for the heads up!

06-25-2003, 10:47 PM
Has anybody tried blurring reflections in post?

06-25-2003, 10:48 PM
Hey Bob, do you know if raising the ray recursion limit affects how many rays are in the blurred reflections doohickey? That might give you a little more control over it...

06-25-2003, 10:55 PM
It shouldn't, the only thing that would control is how many bounces surface to surface. That would be good if you were reflecting two blured surfaces together.

I've been using hikari for my blured reflections.

The shades project also has a ref blur shader in it.

Hikari =$30 (cheap)
Shades = free

bluring it in post wil blur you surface, not the reflection. There is a soft reflection image filter in LW. You can see that mangle your surfaces :)

06-26-2003, 02:10 AM
does anyone know if reflection mapping works with HDR or not? I get the distinct impression that it doesn't, when comparing to HDR background reflections...

06-26-2003, 02:26 AM
I always thought it did. It looked like it did anyway.

06-26-2003, 06:41 AM
Aha... it works in a render, but the preview sphere (and VIPER updates) looks as though it's been reduced to 24 bit. Cool, this is better.

though a reflection map is backwards from a Texture Environment sphere projection of the same image, so don't assume they match up should you need to switch from one mathod to the other while remaining consistent.

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