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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.
Tim Courtney suggested reflection override controls. When I added them,
then the underside of my rendered pneumatic pistons (oriented much like the
engine compartment of the trains), were much darker than I desired.
Willy Tschager suggested ambient and diffuse override controls because he
was having problems when using LGEO parts. I've coded up 3D fractal
generators that use ambient, diffuse and reflection surface models, so I
knew that Willy's suggestions would help reduce the overall darkness.
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.
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
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Message has 2 Replies:
 | | Re: Sand Green and POV
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| "Kevin Clague" <kevin_clague@yahoo.com> wrote in message news:H90qHs.CCn@lugnet.com... (...) I suspected as much when I really started to look at it after you noted that you were using a shadowless light source. [ ... snipped ... ] (...) of (...) (...) (22 years ago, 20-Jan-03, to lugnet.cad, lugnet.inst, lugnet.cad.ray)
| | | Re: Sand Green and POV
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| "Kevin Clague" <kevin_clague@yahoo.com> skrev i meddelandet news:H90qHs.CCn@lugnet.com... (...) I have found that putting a shadowless light _exactly_ at the camera point makes sure there are no visible areas showing only the 'ambient' color. In (...) (22 years ago, 20-Jan-03, to lugnet.cad, lugnet.inst, lugnet.cad.ray)
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Message is in Reply To:
| | Re: Sand Green and POV
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| "Kevin Clague" <kevin_clague@yahoo.com> wrote in message news:H90L2r.HM2@lugnet.com... (...) 2.0.1.5 (...) [ ... snipped ... ] That is good news. I suppose I should look closer at the generated POV code before making assumptions! It must be the (...) (22 years ago, 20-Jan-03, to lugnet.cad, lugnet.inst, lugnet.cad.ray)
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