View Full Version : Reflection falloff

01-12-2007, 05:36 PM
Hi all

I'm very new to Lightwave but I wondered if any one could help me. I have a surface with a logo sitting on it. I have set the reflection to 25% but the whole of the logo is reflected, whereas I wanted to have say half of the logo reflecting on the surface. I guess there is no easy way, so an explanation for a dumbo would be great.

Thanks all

01-13-2007, 01:06 AM
The reflection level is for the amount of reflection rather than say how much is being reflected.

Fall offs are usually done with gradients. Though I have not used the nodes editing feature yet, I am sure there are some better ways now too.

Also there are many ways to do this. You can look in the tutorials section for videos on using the surface editor and gradients and you have some ideas.

But a quick set up to get you rolling:

Click the T button to the right of Reflection in the surface editor for the surface you want to reflect the logo. This opens the Texture Editor.

Change the layer type (top right) to Gradient.

Change the Input Peramiter to Distance to Object

Select your logo as the object from the dropdown list.

Click in the middle of the white strip to create another Key and slide it down to the bottom. Enter 0 in the Value field.

Now you can slide this key up and down with the little arrow on the left. This will set your fall off gradient. But for now leave it at the bottom. You can change the key at the top to something less than 100% - its default. Do this by clicking on it and then entering an amout in the value field. So you could go from 0 to 40% as an example.

So you shoould have a gradient of black at the bottom and white at the top.

Now one important factor is the amount in the field next to where it says "Bottom" this is the distance of the fall off. So at this distance the effect will be whatever amount this key is set to. In this case it would be zero.

So at 1 meter from your object there will be no reflection. At the point of your object the reflection would be whatever percent you have at for the top key.

So depending on the size of your objects this will have to be adjusted. You should do this first otherwise it will mess up your keys. If 1 Meter is good then just leave it.

This is your basic set up.

Now you should have a reflection fall off in a radius going out from your object, wherever it is placed on the surface. This is probably a pretty workabe solution for this basic type of set up. Though I am sure someone will come along with another maybe even better idea. But if you look at those videos and poke around a bit you will see some other possibilities too.

01-13-2007, 05:44 AM
Cheers for that Richard.

Did what you said but getting some strange results (black fade at bottom of logo) any ideas?

01-13-2007, 10:32 AM
Hi bert,

I think I have what you want. If you are using LW9 I have posted a screen shot using Nodes, however, you could duplicate it easily with the standard surfacing also.

Basically I have a 90 (degree) incidence angle being driven by the normal of the flat plane. The two gradients control reflection amount and reflection blurring (which I have very little, the gradient is like 0 - 1%). You can see how I have the nodes attached to reflection and reflection shading.

The rest of the Nodes just make the tile pattern and make the plane transparent the farther from the camera you are; just along the horizon plane.

The next shot is the flat plane with an object on it. I bumped up my actual reflections so you could see the falloff better. If the height of the object falls within the distance to reflect, you will see the whole reflection (like if the object is farther away, but it still fades out).


01-13-2007, 10:37 AM
BTW the job I am using the plane for is for logos, so I don't have any shadowing on the plane object.

You'll have to play with the reflection gradient to get it how you want, but on that render it was 0 degrees at 25%, and 45% at 0% reflection. (on the node version this equates to a key at 0 and .5)


01-13-2007, 02:13 PM

Here is a ZIP file. I modified the object and scene to have reflections, very tough if not impossible to have *pure white* and reflections.


01-13-2007, 03:34 PM
Cheers Mark

Thats great... its looking better already!

01-13-2007, 04:08 PM
Cool, glad I could help out.


01-05-2011, 09:04 AM
Sorry to dredge up an old thread, but I'm trying to create much the same effect myself on a job and this solution doesn't really work the way I'd like (though I do appreciate the help!). The incidence angle gradient only affects how much transparency is rendered on the surface as a whole, rather than having the individual objects being reflected on the surface each fading off (like in fog) as they get "further away" from the surface.

Here's a good example of the effect I want to achieve (this is done using a plugin in C4D):

And here's how it looks in my scene using a gradient tied to incidence angle in LW:

As you can see, the reflection is a flat falloff - the surface gets less reflective as the angle changes (as the perspective shifts). As a result, the objects in the distance have full reflections, while the ones close to the camera have none.

I suspect it's something that can't be done using the built-in nodes, but I'd love to be proven wrong. If not, does anyone know if there's a plugin shader or node available anywhere to create this effect? Something like the one for C4D - here (http://www.mdnx.de/DistFalloff/Dist_Falloff01.html).

Any ideas gratefully recieved!


01-05-2011, 10:02 AM
One way could be to setup a gradient alpha
transparency based on Y coordinate for the
reflected object only, you can use a Logic node
with Spot Bounces input for excluding the object
from this gradient transparency.

91553 91554


01-05-2011, 10:22 AM
Thanks Denis. Wouldn't this still affect the whole surface equally though (so multiple objects wouldn't be possible)?

Ironically, many realtime game engines use this effect for reflections on flat surfaces. As they can't raytrace in realtime, instead they draw extra polys, but fade them out as them advance away from the surface normal - reducing the number they need to draw.

01-05-2011, 05:14 PM
There's also Denis's own Reflection node which could probably do this with its decay setting.


01-05-2011, 06:50 PM
I got this with Reflection Direction node:




01-06-2011, 07:35 AM
Cheers Waxsteel - DPont's reflection node works really well for me (Thanks Denis!).
I'll have a look at sensei's node solution too, though TBH I'm not great at working with nodes