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"Kevin Clague" <kevin_clague@yahoo.com> wrote in message
news:H90qHs.CCn@lugnet.com...
> Mike,
>
> In the first image, there are no shadows. What you see are reflections.
I suspected as much when I really started to look at it after you noted that
you were using a shadowless light source.
[ ... snipped ... ]
>
> Ambient light comes from *all* directions, and therefore creates no
> shading. Diffuse light comes from a specific point, and therefore can
> produce shading and shadows. In POV-Ray, diffuse means the shading part of
> rendering and is controlled in the surface description of the model (it is
> packed into the Color definitions by L3P.) Shadows on the other hand are
> defined by the light sources themselves.
>
> LPub automatically turns off shadows in building instruction images
> (whether you want them or not (do I feel another option control request
> brewing?)). The default settings for ambient and diffuse used by L3P are
> 0.4 for ambient and 0.4 for diffuse. In my previous experience with
> lighting models, it was my understanding that it was desired to have ambient
> + diffuse + reflection equal to 1, so when I turned off reflections, I
> modified ambient and diffuse so they totaled one.
>
> Back to my pistons that were too dark on the underside.... I realized
> that the undersides were darker than the tops because the diffuse light was
> lighting the top, but not the bottom. To reduce this brightness difference,
> I increased the ambient levels, and decreased the diffuse levels, but made
> sure they added up to 1.
>
> For sport you can try two extremes: ambient 1.0, diffuse 0 (which will
> give you shading less images like LEGO uses), or ambient 0 and diffuse 1
> (which makes any unlighted surface black. There are those that render
> building instructions with only ambient (before the ambient controls, they
> used the POV-Ray quality settings to make this happen.)
>
> LPub/L3P lets you define how many light sources you want and what their
> placements are, and those lights are used when creating building
> instructions. So if you want a different lighting configuration than what
> L3P defaults to, you can set that up in the L3P->Lights tab of LPub's
> configuration controls.
This is really useful. I need to sit down with a less complex model and run
through all of the various settings.
>
> On the topic of patience, I feel the same way. I'm new to building
> instructions, and you and Steve Barile have been at it a while. Thanks for
> your patience and input on how to make LPub better suite your needs. I'm
> enjoying the synergy that is happening on the topic of building instructions.
>
> Kevin
Happy to provide input and I appreciate your interacting with the community
so openly.
Mike
--
Mike Walsh - mike_walsh at mindspring.com
http://www.ncltc.cc - North Carolina LEGO Train Club
http://www.carolinatrainbuilders.com - Carolina Train Builders
http://www.bricklink.com/store.asp?p=mpw - CTB/Brick Depot
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Message is in Reply To:
| | Re: Sand Green and POV
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| Mike, In the first image, there are no shadows. What you see are reflections. The reflection of the smoke stack on the top of the engine compartment looks like a shadow because the smoke stack is darker than the abient light you see other places. (...) (22 years ago, 20-Jan-03, to lugnet.cad, lugnet.inst, lugnet.cad.ray)
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