Problem -- default cutoff value [Reflections] in Vray material using Falloff

V-Ray V-Ray for 3ds Max Issues
1

Hi all,

There seems to be a problem with the default cutoff value in Vray material using a Falloff map.
The default value of 0.01 seems to be way too high and produces no reflections or a sever cutoff/edge when using a Falloff map.[SEE images below]
Have had this problem a few times now & can consistently reproduce the same issue.

Is there some way to change this default value in Vray material??? So that I don’t have change all mats manually or with scripts.
Thanks

2

Never had this problem before, using a falloff mat.
Could it be something else, or is this value “unit related” and your max units are out.
Upload the file and I’ll see if it happens this end?

3

All my work is Architectural work so it’s all to scale. I do use meters mostly for

[I’ll upload the scene later today when I get time …THANKS]

Here how I can reproduce it every time--

Try setting your falloff map to & to the following colours 0 & about 22

Look straight at the object

…Happens to me every time

Could it be IOR stuffing up the Falloff map???

Cheers

4

Ok, done some quick tests and can’t reproduce the problem.
The reflection values are so low that I can’t even get a reflection on the surface! - which is what appears in your first image.
So if your material colour is black and its not getting any illumunination is will render black.

5

Here is the scene…http://www.3dmk.com.au/3dmk-vray/Reflection%20Cutoff%20SCENE.zip

I forgot to tell you to make sure you look at the Vray RAW-Reflection layer as it is easier to see the reflection cutoff.

I did also notice just then that the cutoff gets worse as the IOR gets lower

Thanks for your help

Cheers:)

6

Spent the last hour trying heaps of things, new scenes, different units, reset renderer, new camera’s, using a mix map,… etc. etc. etc.

The only way I can get it to render correctly is to change the view axis in the falloff map to use the local Z.?

7

This might happen if the material reflects something is way too bright; the default values work fine in many cases though.

Best regards,
Vlado

8

[quote=“instinct, username:instinct”]
This might happen if the material reflects something is way too bright; the default values work fine in many cases though.

Best regards,
Vlado
[/quote]

Thanks Vlado

This appears NOT to be the case this time as when I turn off the Falloff map & just use the same reflection value the cutoff of 0.01 works fine.
It must have something to do with the falloff map as it only happens when I use this map type.
It appears that when Vray looks at the falloff map & the straight-on value is 0 it figures that this is below the Cutoff value & doesn’t render any reflections there. As the falloff angle increases, the Reflection value is above the cutoff & it renders reflections fine.
I will do a test also using the inbuilt fresnel falloff in Vray Material & see if it’s any different to the Max one.

Thanks
Jamie

9

WOW thank you for this post! I had exactly the same problem with a fresnel reflection with a low value for the IOR (les than 1.3 or more than 0.85). I’m trying to make a car shader with a blend materail and I got those cutoff all over spending hours trying to nail it. Thanks to you, I just discover the cutoff value!!!

10

Hi,

if you just want to disable all vraymtl cutoffs anywhere in your scene, you can use

(getclassinstances vraymtl).option_cutoff = 0

or change the value to whatever you want.

Best regards,
Michael