I was experimenting with different light sources in Carrara (ver 7) the other day. And I wanted a soft fill light, similar to what photographers use in studios sometimes. You know, like a light box that softly light up the model without casting any sharper kind of shadows. So I simply created a plane primitive and made it glow with the Anything Glows light.

Then I thought to myself, wait a minute, there's something called Shape Light. The manual doesn't really explain the shape light, it sort of just mention it. But once added to the scene it appears as if you can make it rectangular shaped, which should be very similar to my above attempt to make a plane glow. So that would be my first question, am I right in assuming that a rectangular shape light is similar to make a plane primitive glow with Anything Glows?

Because it just seem to almost work the same way but not quite. I get sort of angled shadows, indicating that the rectangular shape light surface is in fact not flat. The light source more resembles the bulb light, where the surface is rounded and emitt light from the center rather than in one straight direction.

And question number two, how does one control the direction of the shape light? The object for the shape light looks exactly like a bulb light in the 3D view, and a bulb light has no direction. Maybe the shape light doesn't have any direction either?

HI Ravenous, try like Populus do: use really a plane to cast the light, and turn indirect light in the render. Another way is to reduce the shadow intensity and turn on softshadow in the effects tab for the light.
Shape light are a little complicated to use since it doesnt show the real shape, but all works really more like bulb lights.

Ravenous:

The shape light is weird to use, but I've found it useful in several specific situations.  One is to simulate a large fluorescent panel light, especially those with a plastic lens covering the entire light fixture.

The shape forms at the hot point of the bulb representation, and the height by width dimensions are perpendicular to the axis of the bulb's base.  The best way I've found to work with it is to jam the bulb, head first, up to the wall or ceiling where I'm using the light, crank up the wattage, and use preview to see what I've got.  It's then a simple task to move it into position, then set the strength as appropriate.

Once you play around with this, you will intuitively know where the shape is in relation to the bulb.

Klebnor

BTW, the rectangular shape light is great to illuminate a screen (TV or monitor) as you can float it just in front of the screen, size it exactly, then it both illuminates the screen, and provides the radiant light projected by the screen.  By playing with drop off, distance and strength you can get a pretty nice effect.

Klebnor (nochmal)

You are right, Area light or rtangular shape are good to simulate radiosity when used in the ground too, but without a real representation of the shape I think its a little hard to setup... well this is in our wish list for Carrara 8 anyway.

Enjoy!

Thank you all for your input, and thank you for the example with the tv. I think that particular example sorted it out for me. I just get a bit frustrated when I read the manual sometimes and they  won't explain the function behind certain features.

Hey Klebnor, that looks really good.  Where is the shape light pointed for this scene?  Is it facing away from the screen or pointed towards it?  I'm trying to get a handle on how shape lights work too  :)

jonstark:

Sorry, I was away for the weekend.

The lightbulb is pointed straight at the monitor screen, that is the tip of the rounded end points at the screen.  It is as close to the screen as I can get it without the light source penetrating the screen.  Since the shape light emits in six directions (yes, the boundaries emit light as well) it can be rotated 180 degrees and get the same effect.  The important thing is to align the shape with the object to be illuminated (and from which the illumination appears to emit).  I buried the edges in the frame around the screen ... if I didn't, the light would either light the frame on the inside or seem to shine from the sides of the screen (if it was larger than the frame).

Basically, I lined up the light with the screen, centered it, then played with the height and width of the rectangle until it filled the screen properly.

Klebnor