reflections, shadows and indirect illumination

reflections, shadows and indirect illumination

Post by matt » Mon, 09 Feb 2004 09:09:37


Maybe I just haven't been paying attention to the Photoworks threads, but
I'm not able to get reflections or shadows on a mirror base when indirect
illumination is on.

Wazzup widdat?

matt
 
 
 

reflections, shadows and indirect illumination

Post by Edward T E » Tue, 10 Feb 2004 05:07:11

What service pack? Reflections and indirect illumination worked in 1.0.

There is a legitimate way to get what you are experiencing.
Check your options under raytracing. You can have reflections set to 0,
though I do not think you can get it to happen by mistake (unless someone
else worked on the part/assembly)?
Check your shadows under scenery to see if they are on, and also check the
individual light properties to insure that no one set 'individual shadow
control' for these lights and turned off their shadows (but I seriously
doubt you would have missed that one)

I'll check what the defaults are in 2.1 when I get the chance, and report
back if they might be a contributing cause. I noticed when changing from
sp0 to sp1 that my default gamma got overwritten. Its possible that SWx
messed with things again when applying the service pack, but again its a
long shot.

 
 
 

reflections, shadows and indirect illumination

Post by matt » Tue, 10 Feb 2004 05:24:32

Ed:

I subscribe to the RBP (random button pushing) method when running P-works.
I learn stuff by accident, and don't use it often enough to remember things
I learned last time.

Anyway, it turned out that I was using a white background and with the
indirect illumination setting, everything was getting washed out. I'm
using sp 2.1. The little preview window showed the shadows. Anyway, when
I changed the background to a dark grey, it worked ok, but then I had a
dark grey background.

How do you get a white background and not let it wash out the shadows and
reflections?

matt



"Edward T Eaton" <ed'remove_this' XXXX@XXXXX.COM > wrote in
 
 
 

reflections, shadows and indirect illumination

Post by Mike J. Wi » Tue, 10 Feb 2004 06:49:23

> "matt" wrote...

Waz-up matt,
Always use these settings to begin with and you'll
be off to a great start every time...

LIGHTING (in the Feature Manager)...
*) Ambient, Directional, Etc.: Turn every one of
them OFF


SCENE EDITOR
Manager...
*) Use a Spherical Room environment (because it's
easier to change two walls then six) and make your
own floor from a surface
*) Or, if you need Perspective View on, use linear walls
and use the PhotoWorks floor. A manually made surface
floor can make perspective not work very well.

Room...
*) Assign the wall materials with a dark gray plastic
*) Change the illumination material type to "Constant"
for each wall (except the floor)
*) Disable "Resize Automatically"
*) Make the room size about 10x bigger than your model

Back/Foreground...
*) Color: Plain with white
*) Reflective Background: Doesn't matter here. Your
walls will be the reflective factor.
*) No fog

Lighting...
*) Select "No Shadow" to start off with


OPTIONS
System Options...
*) Screen Gamma: 1
*) All boxes disabled except for "Display
progress/abort dialog".

Document Properties...
*) Anti-Aliasing: Medium
*) Ray Tracing: Disabled
*) Memory management: Disabled

Advanced...
*) Indirect Illumination: Enabled, set to
first notch
*) Contour Rendering: Model only

Once you have all of this set, do a test rendering.
If it's too dark, change the wall color to a lighter
shade of gray, or experiment with clouds etc.
Always make sure you reset the illumination material
type to "Constant". This is how you "illuminate" the
model using Indirect Illumination (get it?).

Once the model is lighting up, turn on a Directional
light to add Ed Eaton's "Farkles". Adjust that light
if it's too bright.

Lastly, you can experiment with shadows and higher
settings. But don't do this until you've done the
above, otherwise you may unnecessarily increase your
rendering time and not know what to adjust to make
it render efficiently again.

Many thanks to Brian Hill for some of these tips.

Let us know how it goes,
Mike Wilson
 
 
 

reflections, shadows and indirect illumination

Post by Edward T E » Wed, 11 Feb 2004 02:16:04

Nice checklist. I was waiting for the farkles, though I would put that
light in earlier in the process because it will alter your illuminations
scheme.
What is missing is turning raytracing back on (I presume that you mean
setting reflections and refractions to 0 when you say 'turn raytracing
off'?).
matt wants to have reflections in the base, which will not happen if
raytracing is not enabled.
To judge the effect of minor changes to your rendering, be sure to turn off
the option of 'clear image before rendering's. This way you will see
changes live on the screen as new pixels replace the old. I cannot fathom
why anyone would want to clear the image before rendering and lose this
powerful and effective feedback.
 
 
 

reflections, shadows and indirect illumination

Post by Mike J. Wi » Wed, 11 Feb 2004 03:06:15

> "Edward T Eaton" wrote...

No, actually from my tests, when you leave that option
disabled, the 'Number of reflections' defaults to around 3 or
4 (I think, it's been a while) and the 'Number of refractions'
also defaults to a certain number, even though it shows a
different amount and is grayed-out. I was trying to make it
simple.

Maybe things have changed since my last experiments?
However to make things consistant, we should come up with
some good default settings of our own.

How about enabling it and setting it to...
Number of reflections: 5 to 8
Number of refractions: 3 to 4

What do you think is a good start Ed?


I agree

Thanks for the feedback Ed,
Mike Wilson
 
 
 

reflections, shadows and indirect illumination

Post by Edward T E » Wed, 11 Feb 2004 03:28:50

OK, you are not turning off raytracing - you are just turning off the
control and using the defaults.

Reflections should remain at 3-4. You need at least 2 or renderings of
reflective things next to other reflective thigns look wierd, but any more
than 4 and it won't make that huge a difference because there's enough
complexity to fool the eye. That is, unless you are attempting one of those
infinite mirror thingies (like that candle in a mirror we played around with
a year and a half ago).

Refractions are a different story. When the refractions run out, the ray
goes black if it has not made its way out of the refractive material.
Imagine rendering a phonebooth (remember those?). If you have refractions
set at 3, the environment on the other side of the phone booth will look
black. You need to have refractions set to 4 or more in order for the light
to get through the glass (2 panes of glass, each with 2 refractive surfaces)
and show whats on the other side.
I set refractions up higher, experimenting with how much black is acceptable
in areas where the light is just goign to bounce around for a while.
 
 
 

reflections, shadows and indirect illumination

Post by matt » Wed, 11 Feb 2004 09:46:32

Wow. That looks like good information. I've lost patience with it for
now, having got something out of it that was good enough for my purposes,
but next month when I go to render something again, I'll check out this
list. Looks like a lot of work. You've got to do this for every part and
assembly you render?

matt



@news.1usenet.com:

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reflections, shadows and indirect illumination

Post by Mike J. Wi » Wed, 11 Feb 2004 13:22:29

> "matt" wrote...

If you save these settings in your templates, they will be
there, ready to go every time.

Mike







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