On 16-7-2017 9:08, omniverse wrote:
> Thomas de Groot <tho### [at] degrootorg> wrote:
>> On 16-7-2017 1:41, Sven Littkowski wrote:
>>> I never actually used bump_maps before. Now I try to use one, but not
>>> seeing any effect. Can someone assist me?
>>>
>>> The scene contains a stratosphere helium balloon, and the bump_map
>>> should have created the typical balloon surface. However, I don't see
>>> the surface changed. Before posting any images, I show you the scene
>>> file. is there any error the way I do it?
>>>
>>> -------------------------------------------
>>
>> Same comments as Omniverse. I give you here an example from my
>> BeenThereDoneThat scene, the moon in the sky:
>>
>> #declare MoonMap =
>>     texture {
>>       pigment {
>>         image_map {
>>           png "PlanetMaps/MoonMap.png" gamma 1.0
>>           map_type 1
>>           once
>>           interpolate 2
>>         }
>>       }
>>       normal {
>>         bump_map {
>>           png "PlanetMaps/MoonBump.png"
>>           map_type 1
>>           once
>>           interpolate 2
>>         }
>>         bump_size 5.0
>>       }
>>       finish {
>>         diffuse albedo 0.9
>>       }
>>     }
>>
>> That is all that is needed. The bump_size is even rather high but works
>> best for this scene.
>>
>> Note that in order for the maps to be effective you need to add the
>> map_type parameter which seems to be missing in your code. 1 is for a
>> sphere. See docs for mor info on image_maps and bump_maps.
>>
>> --
>> Thomas
> 
> Definitely onto something there Thomas. I was looking at it again because I
> thought there was a reason for the default planar mapping, but I wondered if
> that could be a mistake for this particular thing.
> map_type 1 will wrap around the balloon shape spherically and not need
> translate, rotate or scale.
> 
> But the main thing I was thinking about was to skip the image_map to get a
> better look at what the bump_map is doing. So to try that, Sven, you might want
> to look at it with only pigment { rgb 1 filter 0.5 } or similar. That way you
> can see the normal alone.
> 
> I realized my attempt using my own image file masked the appearance somehow.
> Probably something to do with the bump_map being like an illusion and not a real
> surface deformation for the visible image to paint onto. So using the plain
> pigment color it highlights the bump_map instead of masking it from view.
> At least that's my thought on this.
> 
> Bob
> 
> 
>

You are absolutely right. Best to test with a plain pigment, preferably 
a light one. ;-)


-- 
Thomas

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