Radiosity Quality Settings - what each quality setting does

[Allan Chesney]

I have done some experimenting on the Radiosity quality settings (Settings/Radiosity) to see the difference between them as I seemed to be getting some odd results. It was worth the effort.  The results are in the image below

[jjocsak]

Allan, great info on all 3 posts.

Thanks
Jeff

[Allan Chesney]

Spent the whole day on it - had a great time and very pleased with the results. I am really looking forward to trying it out soon on some real jobs.  Glad you found the results useful.

Allan

[dichroic101]

Allen,

Thank you very much for this information. I ran into something similar, but it wasn't until I saw your post that I realized I could fix it.

Your efforts, time, and information are sincerely appreciated!!
T.

[Allan Chesney]

I am glad it was helpful.

Allan

[ahr8tch]

I have done some experimenting on the Radiosity quality settings (Settings/Radiosity)

Do you mean Settings/ProgramSettings/Rendering/RadiosityOptions?  If I'm on the right page, what does Update Display Every nn Steps control?  I can't see any effect after changing this. 

What does Image Brightness do?  I read the Help and understand that it overrides the 3D camera settings, but should it be set to some value to get the type of light reflections that look so good in your drawings?

This was set as just a room with 7 lights of 60W each. Daylight was turned off to make the renderings quicker and there were no windows anyway. The lamps shades were grey and they were custom set to 90% Transparent to give light onto the ceiling and 10% Emissive so that the shade was still visible. These custom settings are found by right clicking the light, select Properties, Appearance Tab, clicking the colour swatch and the colour swatch again, then ticking the Display Setting Details and moving the sliders. (See second image)

OK, I see the lights in your drawing and I see where to turn Daylight off in the Radiosity Options.  But I don't understand the rest of this paragraph. 

Are the transparency percentage and emissive percentage characteristics of the particular lamp you chose, or is that something I should be able to manipulate using a 4" Recessed Light from the Ceiling Lights in the Catalog? 

Right clicking the light fixture (in my case the 4" Recessed Ceiling Light) and choosing Properties then clicking the Appearance Tab gives me a list of Components and Options to change each of the ones listed (fixture, light, 2D symbol).  If I choose the Component 'light' then click on the color swatch in the Materials group, I don't get the chance to click the swatch again before I get a Material options panel with Filter, Groups and Materials options.  I see nowhere in any of those three groups of options that I can tick Display Setting Details and/or move sliders as you describe.   

When you refer to the 'second image' are you referring to the second drawing in the jpg file?

As you can see, I'm totally lost when it comes to controlling lighting in renderings.  I lack even the basic vocabulary to ask questions; so please understand why I described my results as specifically as I did here.

TIA for any 'light you can shed on this subject' 

rh

[Allan Chesney]

Yes this can be confusing and unfortunately things are buried so deeply. The "Update Display Every nn Steps" only controls how many times the image that is being rendered updates on the screen.  It has no effect on the rendering itself, except maybe slowing it down a little.

Brightness affects overall brightness of the image - I have rarely used it - I generally leave it at zero.

The light element of a light fitting is the only thing that gives out light. If it is inside a shade only open at the bottom, then a big shadow will be cast onto the ceiling.  If you set the Material of the shade to semi transparent, light will go through it and provide some illumination on the ceiling. The "Display Setting Details" is a little tick box on the Material Properties itself.  Suppose you set the lamp's shade to plain blue. If you click the blue swatch you get the Materials List with a bigger colour swatch on the bottom of this dialog box.  Now click this large swatch and you will get the Material Properties and, at the bottom of this dialog box, a drop down list of gloss and other settings. Ticking the "Display Setting Details" box alongside this dropdown list reveals the sliders I referred to.

The Emmissive slider makes any Material emit light. By applying 90% transparency to your blue swatch, will allow the light to shine through (giving a bluish cast on the ceiling) but the shade itself will appear transparent in your image.  By applying 10% emmissive will make it glow slightly (as illuminated fabric would).

Transparency, Emmisive and Specular (shine) settings will apply to the Material.  If the same Material is used elsewhere in your model it will have the same appearance. For this reason it is best to replicate the material and name it with the special settings  (otherwise if you have the same blue on a wall somewhere, it will become transparent and emit light!!).

I hope that clarifies things for you.

Allan

[ahr8tch]

I hope that clarifies things for you.

It does, indeed.

Once again I am in your debt.

Thank you.

rh

[Doug.S]

If the same Material is used elsewhere in your model it will have the same appearance.

I have found that if I apply a material to one object.....then apply that same material to another object (same .bld file) and adjust the material properties on the second object, the first object material properties do not change.  However if you apply the changed material again to anything, it applies whatever settings were last used/saved.

This was discussed long ago on Env forum and not easily found/remembered....see:
http://forum.turbofloorplan.com/index.php/topic,216.0.html
http://www.cadsoft.com/customercare/viewtopic.php?t=4841

"My observation is that if I have a catalog material applied to multiple places and I change any one of them....that change "sticks" to that item and does NOT change the others (but that does change the catalog unless you create a new material or object such as a lite). But if you apply that changed material again, the change is applied to the new location.

And you can tell if the item you are checking no longer is the same as the catalog....when you click on the material...when it takes you back to the catalog...if it takes you to the material directly in the catalog, then it is the same as the catalog.

But if when you click to check, it returns you to the top of the catalog (rather than your specific item), then the material you have on an object no longer matches what is in the catalog....either because you changed the item on the object or you changed the catalog item since the last time it was applied to the object you are checking. "

[Allan Chesney]

I first discovered this issue when I set a wood material on a cabinet to transparent to see how it rendered. The next time I opened TFP and inserted a cabinet it was mostly transparent!!  All the cabinets used the same wood material and now they were all invisible!  Changing the material back to visible fixed all the cabinets also, so as you say it uses the last setting for the materail - that's why I create another if I am likely to use similar settings again.

Allan

[George Smith]

This is a thread about tips/tricks & radiosity, so here's a related tip (from Allan) that might save someone tons of time when rendering different views:

The Advanced render creates the whole model, even if you are only showing one room, which is what takes the time. Have you used the Modify Viewpoint?  Using that, you only render the radiosity part once, then reposition the view and do the Raytrace section, so it only takes a few moments for all the following views. As long as you change the names of the file each time in between, then you can get as many image angles as you want without doing the Radiosity again.

[Allan Chesney]

This is a very useful tool as George points out - is often missed but saves a lot of time - and it MAY get better.

I have been playing with the Trial version of Envisioneer 6. Not a lot has changed in the 3D area of the program (which is what TFP inherits) but one huge improvement is the addition to Rendering dialog box, a list of your camera positions.  What this means is that you do not have to guess that you have the same position when you 'Modify the Viewpoint'. You just select Modify, Select the other camera view you want to render, and do Step 2 again - almost instant and the same views that you had in the model are replicated.

The only issue may be if you switch from an inside camera, to an outside one.  Generally outside is best rendered in Basic, so if you do it in Advanced you may not get as good a result, depending what you are doing.  For quickly doing all inside views, or all ouside views, it works really well.

Of course were will have to wait and see if it flows on to TFP 15 in due course.  I suspect it probably will as we have been asking for something like this for some time.

Allan

[Doug.S]

I have not done a study of this in TFP....but re-using the radiosity calcs for another image works OK for small changes in camera positions but may not do so well for large/drastic camera moves such as from opposite side of a room.

I suspect they simply re-use the lighting map of photon distribution...its a good approx. and is a common trick used in video games or for rendering video scenes as the person watching has no time to study the results as they flash by in seconds.

If I find some time I'll try a render using dramatic camera moves to compare to a re-render.....but at least users should be aware the shortcut does come at a price in terms of render quality by not re-doing the radiosity calcs.

Most 3D programs have this as an alternative to save time. Some use "baking" or using a "normal map" or "ambient occlusion" or "photon mapping" "indirect lighting" "multi-pass" "irradience maps" "caustics" "skylight"  "HDR or IBL"  (image based lighting) "object and shadow accuracy in pixels" "antialiasing" etc. for render results control.

Doug.S

[Allan Chesney]

Hi Doug,

I can't say I have noticed any difference creating multiple images from the one radiosity render.  I do it all the time and although I have not tried to do any technical comparison, I have not noticed any difference.  The two images below were done from opposite sides of the same model from the one render.   

I certainly hope TFP inherits the camera view dropdown from Env6, as it then is possible to get the exact same angles as in the model.  I render several times with different colour schemes and it is not possible to match them exactly at present.

Allan

[Doug.S]

I agree my assessment may be wrong.

I ran a few renders today for comparison and they look darn good. Perhaps saving each render and doing a real technical difference analysis would prove differently....but at this point not worth the effort as the differences, if any, seem negligible.

Thus I conclude this method is quite valuable as a time saver.....and if newer version allows for preset camera positions from the camera settings....that would be excellent.

Doug.S