Ground shadows by transparent objects

[ohashi3d]

I've noticed several issues concerning to "Ground shadows" in KeyShot 2.1.21(WinXP32bit).

• Material type "Solid Glass" can't project right ground shadow...always dark!
• Material type "Glass" has possibility of projecting right(pale) ground shadow,
  but needs drag-and-drop operation from Materials Library...
  ...in another words, when double-clicking object and changing Material to "Glass"
  on Option window, the object still projects dark shadow!
• Changing transparency of Material type "Glass" can't change darkness of
  ground shadow dynamically...needs save and re-open bip file, then refreshed.
• Once getting pale ground shadow by Material type "Glass" with drag-and-drop
  operation, the object still project pale ground shadow after changing Material type
  "Glass" to another opaque material on Option window.
  But saved and re-opened, ground shadow is refreshed/matched to opaque material.
• Once Labels mapped with Material type "Glass", the object projects dark ground
  shadow when re-open the bip file.

...yeah confusing and complex a little, so I attached several images and
sample bip file.

In test_101023_01.png:
Box#1 and #2 are same setting as 100% white "Diffuse" material.
Plate#1 is "Glass" material (two sided), and plate#2 is "Solid Glass".
Box#2 is bright nearly same as box#1, but the ground below plate#2
is dark...looks failing to catch the light through plate#2.
And, plate#1 has a label but keep transparent for ground at this time.

In test_101023_01.png:
Once saved and re-opened the bip file...plate#1's transparency for
ground is lost...plate#1 projects dark shadow same as plate#2.
(But in case of no label on "Glass", transparency is sustainable after re-opening.)

In test_101023_03.png:
Plate#1 is set as "Glass" by drag-and-drop operation from Material Library at first.
Then double-clicking plate#1 and changed to opaque material.
But plate#1 is still transparent for the ground.

In test_101023_04.png:
Once saved and re-opend the bip file...irregular transparency of plate#1 has gone.

...hmm, interesting but strange behaviour

Thanks in advance,
kyosen

[guest84672]

We will check into this. 2 things, though.

- Make sure that you check "two-sided" when using the "Glass" material
- Check "Ground indirect illumination" in order for glass not to cast a shadow.

In addition you want to increase the raybounces so you get rid of the blackness in the glass.

Thomas

[ohashi3d]

Hi Thomas,

> - Make sure that you check "two-sided" when using the "Glass" material
--
Yes, I set "two-sided" as shown on my sample bip file.

> - Check "Ground indirect illumination" in order for glass not to cast a shadow.
--
Oh, OK...yeah enabling "Ground indirect illumination" may be one solution.
I feel ground illumination is too shiny a little, though...

> In addition you want to increase the raybounces so you get rid of the blackness in the glass.
--
Hmm, blackness in the glass is another issue which I intended to post in near future.
I feel numbers of raybounces may be not fundamental solution, so far...

Anyway, thanks for your quick response!
kyosen