There are some issues that you may run into while attempting an Advanced (radiosity) render (View /Render 3D Real View) so hopefully these suggestions will help.
1. Interior lights do not work (they go out during the rendering phase).
If you have windows in the room and the sun turned on, then the light coming in through the window may 'overpower' the interior lights and they will go out part way through the render process - usually right near the start (see images 1, 2 and 3).
The process seems to work somewhat like a real camera would work - if there is enough light in a room a camera would take a reasonable photo using the light through the windows. In the real world if a room is too dark you turn the lights on or turn the camera flash on. If a camera flash was set on automatic and the room was bright because the sun was coming in, the flash would not operate and the camera would take the photo using just the light through the windows. In effect this is what is happening when the rendering takes place. The room can be 'too bright' from the light coming in through the glass of the windows so TFP will 'turn off' the interior lights. It seems to be that if the sun strikes the glass of the windows, you will have the 'lights out' problem.
Possible Work-arounds:
- Turn the sun off (it will be dark outside the model - as in Jack's overhead image in the Gallery - Image 4 below)
- Set it to overcast - this will dull the sun's light and may be enough to keep the lights on.
- Set the sun angle or time of day so the sun does not strike the glass.
- Make the roof overhang wide enough so that the sun does not strike the glass. (not enough by itself in the example image 5)
Also, the background image (hills, sky etc) is not illuminated by the sun. This can be used to work around the issue too, because it means that you can still see the backround through the windows, even with the sun off. The drawback is that any forground things you have inserted outside the window would be black, except for any light going through the window from inside (image 4).
Any or a combination of the above will
usually solve the problem (see image 6).
All this applies to Advanced render only - Basic render should be OK (but no where near as realistic of course).
2. A single freestanding wall, outside of a building, renders black.It appears that a single piece of freestanding wall or a single wall that sticks out from the building, will render black (in Advanced Radiosity) because it is interpreted as an interior wall and only accepts artificial lights or sunlight through glass. It only affects the wall surface, baseboard and other trim and mouldings will render normally.
Work around Make the free standing walls out of 4 narrow walls joined so they make a room and pushed together to appear as though they are one wall. TFP will interpret this as a 'building' and automatically change the wall appearance to Exterior which the program will deal with correctly. Bit of a pain to do but it works. Again this is only in Advanced render - Basic is OK.
Another option is the use the Wainscott (Wall Properties - Trim tab) and make it the full height of the wall and set it to your wall colour so it covers over the wall surface - the Wainscott renders correctly. (See the later post in this thread).
Allan
Thanks again Allan for your excellent tips and clear explanations.
Your words reminded me of a couple tips to add here....
Consistent with real photography and interior vs. exterior (sun) light and the limited dynamic range of exposure....
1. For the exact same camera settings/position....you can render a scene twice (with and without the sun "on")....then combine the two images in Photoshop, or similar program with layers, and use the best parts or blended parts of each to get the desired results.....sometimes much easier/faster and with more control than trying to get one good render from TFP.
2. Photoshop and other similar programs can now combine 2 or more images easily to make an HDR (high dynamic range) image to get the best of shadows and highlights without "blowouts" (white only in places not desired) and "mud" (black in which should be dark gray shadows). Simply render normal, under, and over exposed images and combine them into an HDR tool to yield one great image with a large range of bright/dark yet still see everything.
Don't confuse HDR with .hdr or hdri images that are used as "lighting" and reflective rendering for more realistic rendered 3D views....TFP does not have this capability but many 3D programs such as Carrara and Bryce do. See some explanation here:
http://en.wikipedia.org/wiki/High_dynamic_range_imaging
http://www.cambridgeincolour.com/tutorials/high-dynamic-range.htm
http://gl.ict.usc.edu/HDRShop/
Doug,
I do a lot of image blending and as you say it works well.
I have added some test images to the original post. Run out of time last night (2am!) so have added them today.
A combination of the workarounds seems to work best in this situation (40 lights). It was interesting that changing the wattage of the lights made absolutely no difference - presumably the 'auto exposure' compensates. Quite different behaviour to V12.0.
It also made no difference rotating the building - the right hand wall was always the brightest. If the sun was not shining into the room, whether I rotated the building or the sun, it did not change. If the sun was coming through the windows it did change.
During the rendering I noticed too that the light through windows always starts appearing on the rear right and moves forward, then to the rear left and moves forward. If you render at lower quality levels, this effect can get only part way before it completes the whole image. All the renders in the previous images were done at quality 5 for this reason.
There are still a few issues in radiosity rendering that need to be sorted out. It could be a real minefield for newer ones.
Allan
similar issues in Env (TFP parent) and workarounds....look here...
http://www.cadsoft1.com/customercare/viewtopic.php?t=5469
Jack Zimmer has posted a workaround on the Envisioneer forum that works in TFP for anyone having problems with black walls (Free standing walls on the exterior that are not connected to make a room), so I thought I would pass it on.
It is only the wall's surface that renders black (on Advanced render) - baseboard, chair rail etc render OK. The workaround is to create a new wall and on the Trim tab select Custom and create as new Wainscot that is the height of the wall so it becomes a new surface for the wall and renders correctly. Once the wainscot and wall is added to the catalog it becomes available to use on the other walls too. For existing walls with the problem, hold down the Shift key and select each wall, right click and Replace with the new wall with the full height wainscot.
Check the link in Doug's post above again if you need more details and explanatory images (they are on page 2 of the thread).
Allan