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RenderWorks daylight Internal render Options


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Orlando,

Interiors are extremely difficult to light well, and no solution will suit all views of even the same scene. Even changing views changes the way light effects everything.

I have found that using one Directional light for the sun and Area Lights filling the windows to represent the "atmospheric" light give the best simple approximation of sunlight coming in through a window.

Other fill lights with low intensity can be added to help the illusion of light bouncing around the room

In addition using Custom renderworks with Final Gather usually helps (but can slow up render times)

The attached were done with Radiosity on a fairly coarse setting (for speed) but you can get "most" of the same effect with Custom and Final gather set at about 1m and 50%

In Picture 26 there is

A directional light 500 Lux for the sun

An Area light in the window 1000 Lux Smooth falloff

An area light behind the view point for fill 80 Lux smooth falloff no shadows

An area light on the other side of the island bench for fill against the far wall 250 Lux sharp fall off shadows on

Ambient 26%

In Picture 18 it's much the same but with another Area light placed on the floor where the sun hits it 200 Lux smooth falloff no shadows to provide the reflected "glow" from the floor reflection.

All of these extra lights are to improve the details of the way the light falls in the room. Start with putting area lights in the windows.

Some people use HDRI's as lighting as well as a Sun, and Final Gather in Custom RW or Radiosity, but I've not had reliable success with this approach personally.

good luck

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I have found that, as Nicholas suggests, an exterior directional light coupled with one or two area lights in the window areas are often sufficient for interior illumination with Custom Radiosity coupled with Final Gather. In this situation I've also found it best to turn ambient lighting off altogether, or just set it at 2%-3% (using it to control contrast more than the actual lighting).

Dan Jansenson

ps: please forgive the plug: the new Remarkable Renderworks book published by NNA, of which I am the author, has a chapter describing this exact process with precision, including an exercise file.

Edited by Danielj1
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  • Vectorworks, Inc Employee

Dan,

Although I have not yet seen your new book, I have no doubt that anyone who's using Renderworks would most certainly benefit from it. Getting good quality renderings takes a LOT of time experimenting with SO many variables. Judging from the exhaustive tests and images you've produced over the years (using Renderworks), this book will easily pay for itself in no time. It will get users creating much better images in far less time.

BTW: When is the book due to ship?

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Matt, thank you very much for your kind words, I greatly appreciate it.

I'm not sure when the book will be shipping. I understand NNA is taking pre-orders right now; I would expect the book to ship within a couple of weeks perhaps. Sorry, I'm not clued-in to that side of things.

Dan J.

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Hello Again,

Nice tips, thx very much. I never use radiosity because every time i try it turns too bright, and the obvious it takes too long.

Custom renderworks also takes enourmeous time wheen rendering with HDRI (at least HDRI DAY).

As soon as i finish the project in hands i will try this settings.

THX again, i will post some pictures then ok ?

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Hello Again,

I never use radiosity because every time i try it turns too bright, and the obvious it takes too long.

All of the different rendering modes need to have the light adjusted to suit them individually. I've always assumed that Radiosity is brighter because the surfaces are receiving light more than once (from the bounces), but this could be entirely false.

Using Custom Radiosity and turning up the size (>0.5m) and down the energy and accuracy settings(<65%) can make a huge difference in time with "relatively little" difference in visible result.

HDRIs do add lots of time, but the shadows and reflections for exteriors and objects are so much nicer. ;-)

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The Renderworks Help documentation is sparse on how to get good rendering results. The information is mostly a glossary with very little guidance on how users should go about setting up lighting of different types.

The new Remarkable Renderworks manual by Daniel Jansenson addresses that issue and it is a must have for those who want to achieve good results from Renderworks.

http://www.nemetschek.net/training/guides.php

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Thank you, Mike, for your very kind words, they're greatly appreciated.

Generally auto-exposure should not, in itself, yield overly-bright results (but as I mention further down, YMMV). The built-in mechanism of the auto-exposure setting will tend to cause the lighting to adjust to a pre-set average-exposure standard for an averagely-lit image. Including too many or too few lights and then rendering with auto-exposure on will often result in properly-exposed, but low-contrast images. That is, it will often lighten up the dark areas of the scene (shaded areas) in a way that some may find unattractive. Your mileage may vary, however, especially when using HDRI lighting on exteriors. In any case, make sure, when using the auto-exposure setting in the Custom options, that it is set to 100% (or less); you'll often get excessively bright results if it is much higher than that, although it is a convenient setting to use at times.

In my own work I've found that a scene tends to be too light either when auto-exposure is off and there are too many light objects (or they are set to be excessively strong), or when ambient lighting is set excessively high (or, as mentioned, when the auto-exposure setting is much above 100%). But other people's results may vary, so it is worth experimenting until you find a combination of settings you like; it's a bit hard to make a generalization because of the wide variety of conditions you may encounter.

In general it is best to use the fewest possible number of light objects. Users new to Renderworks often assume that if a real-life design has many light fixtures, the Vectorworks model must have many corresponding light objects as well. In reality, it is often best to use the Renderworks light objects simply to illuminate a scene, and then use models of light fixtures that don't actually cast light, but only appear to do so (using, for example, the Constant texture to simulate a light-emitting object such as a bulb) in order to create the appearance of reality.

Rendering speed decreases in direct proportion to the number of light objects used in a scene (because of the number of calculations that are required). For this reason it is often useful to think of a scene as a kind of theatrical stage set, containing props that look like real lights, but where the actual illumination comes from hidden light sources (and in our case, as few in number as possible).

An exterior view can sometimes appear to be excessively bright when using a relatively large number of light sources and types simultaneously: HDRI, combined with very bright directionals, with added spot lights (and sometimes inadvertently duplicated directionals as well) will often yield unacceptable results. In this situation it is useful to employ a kind of abbreviated scientific method in order to pinpoint a good solution. Turn all the lights off (except for HDRI, say), and then do a successive series of quick renderings, turning on additional light sources in sequence until you detect the problem.

Note that rendered sheet layer viewports will sometimes yield results that are a bit different from renderings done in the design layers, due to a variety of factors. Again, experimentation is useful here, but keep in mind that if you render in design layers, you can use the Render Bitmap tool to create a series of test strips, each with different light/rendering settings. The advantage here is testing speed (since you'd be rendering only a portion of the entire scene each time), and also the ability to compare results side-by-side, evaluating the best combination of rendering and lighting settings. Since the bitmap that results is an actual object, you can use the Data tab of the Object Info palette to save information with each bitmap test strip, and in this way maintain a kind of library of test results for different scene types. If you only seriously render a few times a year (as I do in my real-world office work) it can really be useful to have available, as a memory-jog, a saved bunch of test strips side by side, with the settings info for each of these readily accessible.

One other scenario in which renderings may appear too bright can happen with multi-layer models, in which light objects can be found on different layers. Sometimes it is easy to forget that a sun has been placed on each of the layers, only to be shocked at the final result. As a simple practice, I find it convenient to have the Visualization palette open to the light tab while setting up a rendering. This way I can see how many light objects are in the model (in case I forgot any), and can control their status directly from the palette.

By the way, there is an extremely useful FAQ article in Vectorworks Help that covers many of the basics of radiosity rendering. To access it, launch VW Help, and in the search box at the top enter the title: Frequently Asked Questions about Radiosity.

Dan J.

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  • Vectorworks, Inc Employee

Hi Dan,

I'm thinking about that test strip idea. If the user's using Sheet Layer Viewports, They could make a copy of the viewport and crop it into a test strip. Then they could make multiple copies of it, apply various render settings (and even adjust lighting). This could be an advantage as various test strips could be setup and then all selected and updated at once (while you're out getting a latte). Of course, you'd lose the speed comparison unless a script could be written to record the times for each. The cool thing about this is that all the settings will remain with each "test strip" (and can possibly be copied to other viewports via the eyedropper?).

Matt

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