Bump doesn`t work without blurring the bitmap

[JAPAN_DIGITAL_IMAGE]

I noticed the other day that a bump map would get weaker the less the bitmap I use is blurred. If I set the blurring to 0.01 (the least amount possible), bump map doesnt seem to work at all.
Why is that and can it be fixed?

Thanks a lot!

[rivoli]

this is something I never noticed, but I usually turn off filtering altogether for any map in scene, and bump always work as it's supposed to..

[pixela]

I never noticed this too but I must experiment with it.
Actually filtering and blur is never clear for me.

this is something I never noticed, but I usually turn off filtering altogether for any map in scene, and bump always work as it's supposed to..

When you say you turn off filtering altogether, do you mean the setting under Vray Global Switches rollout to filter maps? If not, which setting do you mean?
I always thought that this setting is for enable filtering only for GI- I don't know if I am correct.

If you remember our big discussion thread about noise problem and new DMC sampler in Vray 2.0, last week I was thinking if this noise problem could have any relation with the filtering because in that scene, I turned off all the bitmap filtering for anything and set to None through a script.
Just an idea.
But honestly, I don't understand the filtering and bluring clearly and I would like to hear your methods.

[rivoli]

eh, no I actually keep forgetting about that general switch and do it locally on any map I have in scene. I just set the filtering to none, as it is a way to save memory and get crisper details which otherwise are lost in a fog of blurriness.. it helps a lot with opacity maps as well.

as long as noise related problems go, I honestly don't know. I don't think I ever experienced any difference in that regard with filtering on or off, but I might be wrong as I've never really thought about checking that out.

[Morbid Angel]

I used to turn off filtering on bitmaps also for the reasons above. You have to be careful though, in animation you will have more flickering and a bigger impact the sampler to solve those crisp pixels.

[rivoli]

yes, you're right. I forgot to mention that is what usually work for stills, and I don't use any antialising filter either. rendering animations is different, blurring filters can help in that case.

[JAPAN_DIGITAL_IMAGE]

maybe it has something to do with the rendering size too?
I just know that the less I blurred the bump map, the rougher and smaller it got of course, the more I blurred it, the rounder and bigger it got. But at some point the bump couldnt be seen anymore at all...
I also switched between the filtering methods but that didnt change anything...

[Morbid Angel]

maybe show us a frame?

[JAPAN_DIGITAL_IMAGE]

here are three quick captures:
its a bitmap set as bump map
one is blurred at the minimum

one is blurred at 1

one at 2.




I understand that the more I blur, the thicker it looks, but not blurring at all should just give me the original size of mz bitmap, right?
I am confused...
thanks for the replies so far!

[pixela]

eh, no I actually keep forgetting about that general switch and do it locally on any map I have in scene. I just set the filtering to none, as it is a way to save memory and get crisper details which otherwise are lost in a fog of blurriness.. it helps a lot with opacity maps as well.

as long as noise related problems go, I honestly don't know. I don't think I ever experienced any difference in that regard with filtering on or off, but I might be wrong as I've never really thought about checking that out.

Yes I understand. Actually why I thought that it can be about my noise problem is that I set the bitmap filtering to None through a script for ALL bitmaps on scene. So that includes any map on glossiness and reflection channels and thought it might have a relation with this.
Funny thing is that I thought of this when I wake up - not in front of a pc and I was in the middle of a deadline and couldnt test this.
Hopefully by next week, I will test this on an interior.

By the way one question:
If we set bitmap filtering to None, then the blur amount value automatically becomes invalid?
Or what?

[rivoli]

If we set bitmap filtering to None, then the blur amount value automatically becomes invalid?
Or what?

not really.. even though that would be the most logical thing, I guess, but the value is still taken into account. turning off filtering basically gives the same result of a filtered map with the blur value set to its minimum. I just leave the the blur alone at 1.0, and tick none.
I also do that for any kind of map, specular and glossiness included. I like non filtered fine details much better, that's why I usually don't use any antialiasing filter either.

[pixela]

Forgive me but I am still confused.
When the blur value=1 and we set the filtering to None, we have the map as we see in Photoshop?
Or still some kind of blur is added to the map ? Then the only way to make the map as we see in Photoshop is to set this blur value=0.01 ?
Or is this blur value totally disregarded when we tick NONE?

[rivoli]

I understand that the more I blur, the thicker it looks, but not blurring at all should just give me the original size of mz bitmap, right?

that's really weird, I can't make it work like that here. been trying a lot of different combinations..

[rivoli]

When the blur value=1 and we set the filtering to None, we have the map as we see in Photoshop?

I guess it is, at least that's what I always assumed, and it should work the same way if you disable filtering for maps in the vray global switches rollout. in fact, whatever blur value you type in, it doesn't change anything as long as you don't plug the map into the bump slot. I just noticed this while trying to reproduce the problem J_D_I is having. if a texture is used as bump, then the blur value won't affect the map itself (and so it doesn't make a difference for any other material quality), but it still affects the bump.. can't really understand why, and it may very well be a bug, but this is what happens here.
so well, once you disable filtering the blur value doesn't have any effect on the map, but it still affect the bump output. it could be related to the topic of this thread..?

[pixela]

Well here are my experiment results, I am sending you the renders.

01-Global_On




01-Global_Off




01-Global_Off_FilterNONE




01-Global_Off_FilterNONE_Blur=0.01

As you see, I didn't notice any change with global switches or filtering set to none.
The real difference was only with bump slot as you all told.
I am posting my results in next post.