It's my understanding that every light should have an associated camera with it (the Shadow-Cam) which helps enable you to place the lights and determine shadows, etc...  (At least this is what the Poser 6 manual claims.)

However, not every light in my scenes has a shadow cam.  In fact, lately, less than half of my lights have cams associated with them.

Whats up with this?

Thanks!

For some reason,, you cannot save a shadowcam to the light library. You have to save the lights in a PZ3 to keep the cams intact.

And each time you create a light, it should create a corresponding shadow camera for it.
So what you might have to do is delete the lights that don't have shadow cameras
and create new lights to take their  place.
Really, with Poser 6 you only need two or three lights anyway.  One set to
Ambient Occlusion and one to  generate shadows, and maybe another
for highlighting something.  Over the years people have gotten light
happy in an effort to simulate global illuminations, and so people ended
up with far more lights than they really need, which take up resources
and really bogs down rendering times.
You didn't say how many lights you were using, but you should ask
yourself, do I really need this light?  Do I really need that light?
Maybe a good thing to do would be to get rid of all the lights first,
then set up one for Ambient Occlusion and see how your scene
looks.  Then add another for shadows and see how you like that.
Then add another one if you really need it.

Well in P4 you get a "Shadow Cam Lite" for every light, and these are preserved if you save to the Lights palett, or save out a pz3. I imagin P6 is suposed to work the same. Perhaps it's a corrupt file. How are you loading the lights?

I thought only shadowmapped cameras had a shadow cam?

Does lights with raytraced shadows also have one?

I'm simplifying here, but..

All lights have a shadow cam, even IBL. If you enabled depth mapped shadows on a light it gets used. It uses the shadow camera to render what the light "sees". Why? Because if the light can see a particular spot, then that spot can see the light, which means it is lit by the light. Paint it white. If the light can't see a spot, it is in shadow for this light - paint it black. So it sort of makes a black-and-white render from the shadow camera, painting all the objects black or white and saves this infomation. (This is why you can reuse them - the information doesn't need changing unless you move an object or light.)

Soft shadows are made by blurring this hidden shadow camera render. Sort of.

Then later, as it scans the scene for your render with your camera, it consults that shadow cam render for every spot to find out if it was also drawn there and how bright. If it wasn't drawn in there, it assumes it was lit. If it was, it looks at the brightness to determine how much to light it.

I wonder if a missing shadow cam might come back if you enable depth-mapped shadows on the light and render, but I'm just guessing.

I suppose Poser could barf, but light doesn't need it's shadowcam unless you enable DM shadows on the light and render with shadows enabled.