Nasty falloff BUG?

[PIXELBOX_SRO]

Hey guys,

I ve got a simple xray shader where i am plugging a fallof map into opacity slot, i am using self illumination, so no lights in the scene.
Falloff is fresnel type.



i ve tried 3 types of shaders, two vray ones do this but standrad material doesnt.
I am gettgin these ugly buckets all over the place although i am rendering on a single machine!
I ve tried cutoffs, and all sorts, its still there, and always the same buckets.

Any ideas?
Seems like a bug...

M

[PIXELBOX_SRO]

its definitelly the black value thats doing this but why?
i ve tried even the fake fresnel map, settgin the front reflectivity to 0 or 0.001 and its still doing but when i set it to 0.1, it stops doing....but then i dont get the nice transitions as i need them to be in the xray shader.

[Morbid Angel]

its probably the stochastic clip, try switching the opacity mode and see if it helps.

[PIXELBOX_SRO]

Thanks Dmitry ....Switching opacity mode? Could you be more specific? I ve no idea where i could find such function
Cheers

[PIXELBOX_SRO]

Ok help docs...will try in the morning

[Morbid Angel]

this one. Its default perhaps clips it hard...try normal.

[Miro]

Increasing the Min subdivs of the image sampler to 2 or more might help.

[PIXELBOX_SRO]

Thanks but why is this happening?
Shouldnt this be working well in any mode and any subdiv level? Its just a fresnel map in opacity slot...

[Vizioen]

Thanks but why is this happening?
Shouldnt this be working well in any mode and any subdiv level? Its just a fresnel map in opacity slot...

If you would have read the help file, you'd know why:

Opacity mode – Controls how the opacity map works. For more information, see the Opacity mode parameter example below.
Normal – The opacity map is evaluated as normal: the surface lighting is computed and the ray is continued for the transparent effect. The opacity texture is filtered as normal.
Stochastic – The surface is randomly shaded as either fully opaque or fully transparent so that on average it appears to be with the correct transparency. This mode reduces lighting calculations but might introduce some noise in areas where the opacity map has gray-scale values. The opacity texture is still filtered as normal.
Clip – The surface is shaded as either fully opaque or fully transparent depending on the value of the opacity map (i.e. without any randomness). This mode also disables the filtering of the opacity texture. This is the fastest mode, but it might increase flickering when rendering animations.

[PIXELBOX_SRO]

i ve read that obviously it just did not occur to me that if i if i dont use classic opacity map (as one woudl use- leave, logo whatever) it will do this.
Ï woudl have expected it to return errors on pixel basis, not on bucket basis.

btw Ashley, no need for smart answers of such type, i was JUST asking

[Vizioen]

i ve read that obviously it just did not occur to me that if i if i dont use classic opacity map (as one woudl use- leave, logo whatever) it will do this.
Ï woudl have expected it to return errors on pixel basis, not on bucket basis.

btw Ashley, no need for smart answers of such type, i was JUST asking

Sorry rough night

[PIXELBOX_SRO]

np
so anyway, settgin the opacity mode to normal fixes the problem.

Case closed, thanks a lot gents!
M

[Morbid Angel]

Imho it should be default to normal. I think the other modes are there for things like leaves where a hard clip opacity is better for performance during rendering.

[PIXELBOX_SRO]

Yeah it made me think the same

[anthonyh]

hi,
sorry to bump the thread but i just had this same issue where 80% of my image renders fine but there`s a big square in the centre which has 4x the noise and it was `stochastic` again. this seems like a bit of an issue considering it`s set to default. it`s also strange that it`s not consistent, contained within a box centre screen.
here`s a progressive render with a couple of passes that shows the issue big time. it has a fresnel falloff opacity. setting to normal does fix it but i`d just like to add my support for making `normal` the default. apologies if this had already been sorted.

thanks
anthonyh