Shaderlight

Soft Lighting Example

 
QStuff
Total Posts: 54

This is the result of some experimentation in developing a way to produce a luminous light bulb (LED of course) that casts soft shadows.  The bulb is translucent with back to back (facing up and down) area lights inside it.  Area lights seem to be the only way to get consistent soft shadows. Unfortunately their light only goes in one direction thus the back to back arrangement.

Note: This is straight out of Sketchup and Shaderlight—not post processing.

Update: The second image is a close-up screen shot of the light bulb inside Sketchup showing how the area lights are arranged.

Image Attachments
Lamp_Test_2.jpgLight_bulb.jpg
Click thumbnail to see full-size image
awaddington
Total Posts: 373

Great Tip, Thanks QStuff!

awaddington
Total Posts: 373

Unfortunately, still not a perfect solution (albeit this is the closest I’ve seen yet).

Because areas lights only emit light in one direction, no light is directed to the sides and we get a strange sort of “equator” from the back-to-back area light object (see attached).  This is less noticeable in your model because you had a decorated shade so lines and shadows are expected.  Modeling a bare bulb would require some additional area lights.

We still need a light emitting material.

Image Attachments
doubleup_arealight.jpg
Click thumbnail to see full-size image
QStuff
Total Posts: 54

Yes, that dark band is present in my rendering and is obscured by the lamp shade. There’s not much need for a bare bulb.  I’ve posted a request for a sphere shaped area light (or something better), as a feature request.  At least one other product has an “emitter” material setting that can cast light which can give the desired effect.

EGIE
Total Posts: 487

Hi QStuff and Andrew

QStuff, thanks for sharing your experience and your testing!

Some time ago, I posted this little example which is quite similar to QStuff’s solution:
http://www.artvps.com/index.php/discuss/viewthread/721/
(please zoom deep into the first picture into the candle flame)
I built a cube out of 6 Arealights to achieve a uniform illumination, which worked pretty
well. - QStuff, so your “sphere shaped area light” is a very good idea!  :-)

And yes, I often demanded to develop an adjustable option for softshadows by the use of Pointlights and Spotlights as well, which is the most important item in my view (in addition to the development of a real batch render tool). Finally, we experiment with Arealights, because there is no softshadow option!

Even the Sketchup Sun should have a free adjustable softshadow option similar to physical sky, but without the color bleeding from Physical Sky.

Regards, Egie