reflect or refract based on distance???

[andrewjohn81]

I seem to remember Final Render could do this, but I'm not sure of a way to do it in vray.

Can you do a falloff based on distance from the reflection instead of distance from the camera? I know alot of people will just say, "yes, falloff map can do distance," but that's distance from the camera unless there's an option I don't know about.

What I want is to have a character standing on the floor and the floor will reflect him, only it will reflect the feet, but not much else. When the feet lift off the floor the reflection will lessen until they come nearer again.

This sort of option works quite well with extremely blurry objects. It's faster to calculate because you don't have to take as many samples of far away objects. You can fake that on your own. You'll just need to worry about close ones.

Anyone know if this can be done?

[instinct]

Well you can set the mode to "Distance Blend" and then change the second drop-down-box to "object" then you can select an object (most likely a dummy between the two feet then ? ) as distance source.

This will not fade along the character tho....only based on the distance....what you could do tho is use a gradient map and two fall-offs each set to object and one on the bottom one on the top of the Char....no idea if that actually works tho :P

most likely not tho :P



Thorsten

[instinct]

just tried....actually what you want can be done with a single dummy and falloff set to distance blend....see here :



you can tweak it using near distance and far distance

[Dynedain]

That solution achieves the affect, but is dependent on the camera's position. If the camera's distance to the reflection is changing, it could be a problem. It would be nice if there was a way to utilize the reflection's distance from the object.

[andrewjohn81]

I was hoping this could be more automated and based on the normals.

Basically what Final Render does is calculate the ray distance after it hits a reflection and measures that. The distance you give it is based on that.

So, if the ray hits the floor and bounces 5 inches to the feet at the highest point you could put 4.5 for far, and 0 for near. That would make the feet disappear at the top of each step.

What I am actually wanting to do is make some more universal settings/shaders to use over and over again with quick setup time.

We cheat alot, but it's such a pain to explain to everyone how you accomplished something. In order to show them you basically have to do it again for them 2 or 3 times before they get it. It's alot easier to tell them settings to use and hand them a shader.

___________________

another thing is that i don't want to create a material for each object of different size. I want the same falloff distance for each one, but that's it.

[dimo]

Hi,

What would be better, a map that returns the dimmed reflection (with secondary bounces) or a map the gives you an alpha channel for the first bounce distance?

Best Regards,

Dieter

[instinct]

@dyn : the falloff is based on object distance ... camera sholdnt be a factor....no ?

Thorsten

[Dynedain]

@dyn : the falloff is based on object distance ... camera sholdnt be a factor....no ?

Thorsten

I read what you did wrong. I thought that what you had setup was based on the distance of the point on the plane from the camera - which would work as long as the reflection is between the camera and the object.

[instinct]

The reflection falloff is interpolated between the floorplane and a dummy...and using far/near distance it can be adjusted....i´ll do a fly-by tomorrow nite to test it...as i think it shouldnt be camera-dependant.

Thorsten

[andrewjohn81]

did you ever do that test? I'm just curious.

With final render you can give raytrace falloff from where the ray was cast.

That way if you have 50 objects with the material applied it dramatically reduces your rendertime.

That's the only renderer I know with that option.
We get slightly more reliable results with vray though.....like it not crashing max constantly and causing random problems, so we keep to that.

If I remember correctly, when using the falloff with FR it was sometimes faster because it basically ignored what was beyond the given distance and added no more reflection. It worked pretty good.

[mike.edel]

should also be possible to script this (scripted material maybe?) so that the distance-to-camera influences the amount of rays for the glossies

other than that: using the render settings vlado suggested in this thread
http://www.chaosgroup.com/forum/phpB...747&highlight=
the amount of time spent rendering reflections should only depend on how visible they are (the qmc sampler should only take visible effects into account)

[andrewjohn81]

it's not related to the distance to camera, it's related more to the distance the ray travels after it hits the reflective object.
It would have to measure the ray not from the camera to the object, but rather from the first object to the second object.

The camera distance has nothing to do with it.

The way vray is set up now I don't know if that is possible. If it can measure that distance, ignoring camera distances, then it should be possible to do. May be beyond scripting, but should be possible for chaos to create easily if it can do that measurement.

I don't want it to use glossy though. the reason to use this feature is to avoid glossy. It's a quicker way of doing a similar thing.

Imagine a refrigerator on shiny tiles. They would reflect it, but you don't notice the reflection on the tiles that are far away, but the reflection doesn't necessarily get blurrier, it's just less appearant.

[ene.xis]

the reflection doesn't necessarily get blurrier, it's just less appearant.

isn t that achievable easily with a faloff?

[CXStudios]

I just happened to been trying to figure this out myself. At least for what I am doing even the Distance Blend with Object is not working good enough. I need to be able to control the reflection in a linear fashion not spherical.

This should be mentioned in the Wishlist is it's not already there.

[instinct]

Couldnt you do it with Distance Blend in World or Local Space then ?

Thorsten