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Hi,
i notice that bump map, beside the pseudo-relief effect, also tends to give a "darken" effect where it's applied.
Did someone notice this beside me, or am i missing something ?

Paolo

also, i seem to get no bump effect at all with some kind of UV, i.e.w ehn i have discontinuous UVs.
Is there any thing to keep in consideration to get bump working ?

thanks,
Paolo

i mean, how is it possible that i get this ?
one layer, one UV. bump at 100 (maximum) and i barely can see the effect.



Paolo

Strange effects can occur when using high bump values (like darkening). I wouldn't raise bump to more than 50 at most. Most materials I use that have bump are between 1 and 30. Normal maps can do high values better.

thanks for the info about darkening.
but the issue on this object is quite strange. i used a normal to get the effect, but no way to get a bump here.
I passed the scene to a friend, hope he can send to beta guys.


Paolo

Try a different bump map, pure b+w isnt a good idea, also try preview scene 'floor' to judge the strentgh needed. In the render, the mapping is to fine so we cant see whats happening anyway, try doubling the texture scale and zooming the camera in a bit...

In this case a normal map would avoid any darkening.

i tried also non pure BW maps but the effect is always unreasonably weak. I think there's realyl something odd here.
Anyway i solved using a normal map

Paolo

Bump maps work, theres no doubt about that.. I noticed your map has no antialising, try blurring it 1 pixel.

i did. i tried a bunch of different bumpmaps, even blurred ones.
Bump works usually, i agree. but on this geometry it has issues. i also checked it with another user and there's no way you can get a common bump effect here, if not using a normal map. Maybe there's something about geometry but i checked it several times, nothing is broken.
I cant share the whole object but if someone wants to try, i can breack it and send just that piece so one can try himself.. maybe i'm missing something but really i wonder what.

Paolo

Can you post a comparison of renders using bump vs. normal?

Maxwell's bump with blurred BW map. I put 100% intensity bump both in BSDF layer AND in Global bump to get this effect, so i cant get a stronger one that this.



Maxwell's bump with Normal map - same as before, 100% in both places.



And an attempt with Fprime, with same blurred BW map used as bump:



frankly i expect a bump map to behave like in Fprime, as you see it's by far best behavior and i cant get it in maxwell.

Paolo

F-prime one looks messed up too. Looks like the UV's are broken, you could try to position spherical mapping coords onto the neck polys.

yes, leave it alone... UVs are bad and lines are all zig-zag, i didnt build this object. Let's just look at bump effect: Fprime's is way more natural and much closer to what i expect from a bump than Maxwell's.

Paolo

Paolo the f-prime lighting is different, but also maybe the surface normals are all chewed up like the UV's and f-prime isnt using them...
There are issues with bump maps causing a gloss effect if tiled too fine, but I'm sure bump maps work, I use them all the time.

I agree about bump mapping working usually, i use them too. I just notice that they always produce a strange and unwanted darkening effect in the negative areas.
But this case is different, i cant get them work as they do usually since the effect is extremely weak unless i use normal maps.

Paolo