#Shadow effects
15 messages in this thread
Could someone please help me with an issue on shadows.
When rendering scenes with shadow maps cast by spotlights, even with the High
size and High sharpness switched on, the shadows have a palette-knife
appearance and cast soft shadows if the light source is far from the shadow.
The same scene when ray-traced has sharp shadows but with much more detail.
What I want is lots of detail in the shadows (ie where they overlap), but not
for them to be unrealistically sharp when the source is distant.
How do I get soft, nicely gradated, shadows, similar to the tricycle's shadow
on the Caligari spash screen?
thanks to anyone who can help.
David
>>How do I get soft, nicely gradated, shadows, similar to the tricycle's shadow
on the Caligari spash screen?<<
Use a spotlight, and scale the inside of the spotlight cone by selecting the
spotlight, click & drag the mouse while keeping the mouse button down… you
will see a green circle inside the spotlight cone change size….
Hope this helps
Rob
Also, do you have the "Ray" button selected for ray traced shadows?
I have my spotlights with their blue inner cone smaller than the outer white
one, and the light falls off as expected around the centre of the lit area.
And yes, I do have Ray switched on (and Ray switched on in the Render dialog.
Which is a wee bit confusing I find. Not sure what happens if one is on but not
the other… Anyway.)
Result is still that shadows are pin sharp at the edges. I guess that this is
how its meant to be, but I'd really like to get shadows like on the splash
screen – detailed but soft at the edges.
any other ideas?
thanks for help
David
David, try setting the shadowmap size to high, and shadow sharpness to low,
that should give you a nice smooth shadow with soft edges. If that doesn't
work, try the same with ray turned on, but be ready to wait a while.
Let me know how it turns out!
I-Wei, Tech support,Caligari.
I-Wei
I see how its done the first way you suggest, but it seems tricky, and depends
critically on the distance of the spotlight from the shadow. Too close and he
shadow is sharp, too long and it gets lumpy and peculiar.
I cant get a soft shadow with Ray method anyhow. As soon as I set the lamp to
Ray I get a sharp shadow no matter what else I do.
Thanks anyway for your help..
PMFJI David,
But have you tried using mulitple lights? One to make a sharp shadow one to
make a slightly larger soft shadow, and if the whole thing is too dark a low
level light to lighten the shadow area? Of course the rendering time goes up
with each light with raytracing……….
Ken
Ken,
Yes I agree, it reduces the contrast of the dark shadows, but the edges of the
shadows are still pin-sharp. Now in the grey climate of the UK (unlike the
happy folk in Caligari I suspect) the sun shines only intermittently, and the
real world of shardows is one of diffuse effects. So as soon as I generate a
rendered illustration of an interior lit with sharp shadows, the viewer
immediately gets a (quite unnecessary) impression of bright sunlight.
I'm trying to simulate room sets, that we have to build and photograph,
planning the shots before commiting to big $$$ spends. No photographer works
with sharp shadows unless they are making a very specific statement. So its
just a bit disappointing that in TS I can make a really good simulation of a
scene, yet they are all on a bright Californian afternoon, not a grey English
morning!!
David
David,
Here's a thought (from a fellow Limey<g> who's seen the drab days of merry old
England…), create a fuzzy, semi-transparent TXR texture map (possibly a
gradient fill, and use "Intensity" to create it). Place a circle or hex over
the large end of the light, a short distance from it. Texture it with the
created texture, raytrace the scene and you have an instant gel light. This
should give the effect you are seeking.
Regards,
Ian
I remember meeting some photographers from California while working in the UK,
they were always complaining about the light, they felt as thought they were
almost blind.
Some how their ASA 24 film did not produce the same results………
Ken
Hi David,
pmji, but lighting of internal spaces is a very tricky problem in 3D graphics.
We make the assumption "that over there is a light, and this over here is a
wall, and lights emit light and walls do not" but — if you take a glance at
the room around you — you'll see that the walls definitely reflect light to
the ceiling, the floors reflect on the wall, and every object casts diffuse
light on every other object in the scene. Those would be some horrendous
calculations to make.
One trick that may be helpful, if you really need soft interior shadows, is to
paint them directly onto the texture maps used to color surfaces. This was used
on Iron Helix, among other titles… Drew Huffman and Rich Cohen could have
used Electric Image to run the shadowmaps directly, they instead used painted
shadows atop texturemaps to catch the shading in the corners of rooms, the
density changes in shadows beneath a table. Makes animation difficult, but
helps with diffuse interreflection in interior stills.
Regards,
John Dowdell
Macromedia Tech Support
>> Makes animation difficult, but helps with diffuse interreflection in
interior stills.
Yeah, neat trick — I'll have to remember it for some things, but difficult
isn't the word for most animations! <g> Radiosity would be better suited for
that kind of thing.. :-{
>>Radiosity would be better suited for that kind of thing..<<
PMFJI Terry, but I have been reading a lot about radiosity recently, are we
getting it in tS2?
Ken
Sorry.. No radiosity in trueSpace2. I don't think "the door is closed" there,
though.
When you have Ray turned on for a light, you have to ray trace (settings box)
to get the shadows properly..