Simple Interior Lighting in RPR 2 for 3DS Max

Some of you may have seen my archviz scene in the RPR Facebook group. It’s a customised Evermotion V-Ray scene with custom assets. I made it for a realtime rendering demo the team held recently. A demo like this means constraints on the scene: Facilitate a supershort (render)time and no postwork whatsoever, as well as native RPR shaders. As the latter meant manually converting umpteen V-Ray to RPR Materials, the lighting was actually the easiest thing to set up, as I only used two lights and an IBL. As RPR is still in beta, with some additional beta costraints,  I’ve made an effort to explain my workflow setting up the  scene the way I did. Also, if you’re not familiar with Radeon ProRender, here’s how it works:

Radeon ProRender is a Physically Based Renderer, also kown as a PBR. If you’re new to this type of rendering, you’ll notice it doesn’t quite behave like i.e. the Scanline renderer or Mental Ray. Here’s why: It doesn’t matter which renderer you pick, given enough time, patience and elbow grease, they can all give you stunning results. However, a PBR like Radeon ProRender (or others) can really help you create realistic results faster, as they have realism built into the renderer. That’s because a PBR renderer has been coded to emulate how real world items like glass, mirrors, light, cloth, and other items behave in reality when they interact with light -or the absence of it. Because the renderer has been told about how these things behave in a scene when lighting is added (or removed), the renderer tries to predict what the appearance of the items in your scene will be, thereby rendering your scene more realistically – which in turn can save you a lot of time spent on lighting and Material setups. This is why the lighting was the easiest thing to set up, as two lights and an IBL were much easier to deal with than the 200+ textures and Materials that needed converting :-D!

Step 1 – Basic Photometric Light

I started by setting up a working light, and placing it in the middle of the room, so I could see what I was doing, when converting my Materials. For me, this was easier than just grabbing an IBL and cranking it up to the max to see what’s going on in the interior. It renders faster, too.  As a Photometric light emulates real-life  lighting behaviour, it’s your safest bet for realistically behaving light in your scene. Note that I am not saying realistic light – no matter how well-behaved your PBR is, the fact that it renders correctly, will never mean that will automatically look (artistically) right without artist intervention. PBRs and Photometrics crunch numbers – and no matter how awesome they are at that, they can’t replace the human eye (yet ;-))
The Photometric’s position stayed  static during my work with the scene, I spent some time on intensity trial and error. The slider and steps below show my starter settings at their highest, and how they look as AO and GI passes:

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If you’re an experienced Max user, all you need to know is that the light was set to On, default Uniform Spherical, and the intensity was set to 500 cd. If you’re a newcomer to Max, RPR, and setting up lights, here are the full steps:

  • Click the Lights icon the Command Panel
  • In the dropdown, select Photometric (The default choice in vanilla Max)
  • Click Free Light and place it in your scene
  • Leave it to Uniform Spherical, as it will cast light in all directions, which is handy when texturing
  • I set the light to 500 cd under Intensity because I wanted an even light to see what I was doing.

Note: Once I’d added the Directional Light, the IBL, and adjusted my Exposure settings, the final render has the Photometric light set to  3,5. The reason for this being that even though I needed the light, the RPR beta hasn’t implemented shadow settings yet, and the light cast a shadow that threw off the light in the scene, and I needed that dialled down, whilst still keeping some of the omni-light effect of this particular light.

Step 2 – Creating a basic Direct Light

I live in Norway, where the difference between seasons is very tangible. One of the things I love about autumn, is how bright and warm the light is in the middle of the day, as opposed to summer’s often harsh, almost white light. To fake the sunlight, I used a Targeted Direct light, set up as follows:

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If you’re an experienced Max user, the light was given a soft sunny yellow colour, and set at a fairly high angle, as you can see in first slide in this set.  I ended up setting the Multiplier to 0,25 for the final render, letting GI and exposure do the heavy lifting, as described in steps 3 and 4.

  • In the Command panel’s Lights settings, select the Standard dropdown
  • Select Targeted Direct light, and place the light and its target as you like to emulate the sun streaming through a window
  • When working with this type of light, you need to know that RPR treats Standard directional lights like sunlight. This means that the only settings applicable in this kind of light’s Modify  Panel, are:
    • The Intensity Multiplier. There is currently no implemented decay or attenuation for this particular type of light. This also means that as RPR is a Physically Based Renderer, it will render shadows regardless of whether they’re turned on or not, as a PBR uses a completely different lighting model than the ones the Standard lights were intended for.
    • Colour – use the colourpicker next to the Multiplier to tweak the light’s colours
    • Direction –  just use the widgets to position the light and its target.
  • If you’ve not dialled down your Photometric light yet, now would be a good time to do so, otherwise the sunlight will look very washed out, as you can see in slide 3. Slide 4 shows the scene with the Photometric light dialled down
  • As I spent a lot of time tweaking the IBL and Exposure settings to avoid too many burns (except for on the IBL),  I ended up reducing this light’s Multiplier down to 0,25. This is something you really need to  experiment with to suit your own scene
  • Finally, I set the light’s colour to RGB, 255, 231, 211, to make it a bit warmer, before moving on to setting up my IBL

Step 3 – Using the RPR Environment

Now we’ve blocked in the look of the light and the sun, all that’s left, is to let the magic happen by letting GI and Max’ native tonemapping do the heavy lifting for now, as, future versions of RPR will ship with improved IBL-settings and tonemapping tools; The IBL will add GI and light to those two rooms in the back, as well as helping to soften the light and shadows in the scene a bit more. While working with the scene, I «cheated» a little. Because of the constraints I had, I Photoshopped my EXR a little, rather than using Max’ native tools to finetune the IBL to suit my needs.
The Autumn Forest from the now closed Substance Store’s Military Mood Pack is by far one of my favourite IBLs, and I’ve used it in many renders.  What I needed, was a little more brightness, and a little more warmth in the light it cast, nothing more.

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If you’re an experienced EXR-tweaker and IBL user, all I did was nudge exposure up to 0,25 and add a very light red hue via the Photo Filter at 12%, before loading it into the RPR environment, and tweaking the settings. If you’ve not done this before, the full steps are:

  • In Photoshop, load your IBL
  • Go to Image>Adjustments>Exposure and increase Exposure a little to brighten the image – for this particular image, I set it to 0,25
  • Go to Image>Adjustments>Photofilter, we’re adding a little warmth to the image, next:
  • Select Red from the dropdown, and set it to 12%
  • Save and switch back to Max
  • Press F10 to access Render Settings.
  • Scroll down to  Environment and Scene Settings in the ProRender tab
  • Check Override 3D Studio Max Environment – This will activate the Image Based Lighting Group
  • Set Intensity to 1,5
  • Check Image Based Map and load your IBL
  • On loading your edited IBL, you may want to check the Colour Correction settings.
    For this scene, I set mine to 0,5 Exposure, and 1,1 Colour, which meant that I could ease off the tweaking in the Max Environment and Effects editor.
  • The scene now renders very dark because I reduced the settings in the Photometric and Targeted Direct Light.
  • This is because I wanted to  let  Exposure do the heaviest lifting, so we get the lighting you see at the top of the page:

Step 4 -Tonemapping and Render Settings

The scene in the final image is not an uncommon sight up here. It will probably be messier in reality, but the only thing that’s probably more art than life, is the colour scheme: Cabins or houses in the woods often have a more rustic colour scheme, and less tech; The norm a much earthier colour scheme – lots of wooden browns (Think pine, birch, or fir) with reds, some contrasting cools, plant and white or striped rag-rugs, Computers are usually put away for most of the duration of your stay, if you’re just visiting.
I decided that as it was midday, I could get away with a few sins, like a burned IBL, in order to make the interior brighter and more evenly lit, and here’s how I set up my tonemapping and final render settings:

Doubleclick for fullscreen

  • In Render>Exposure>Exposure Control, choose Photometric Camera
  • I set EV to 2.75 in the scene. It was originally 2,5, but I wanted less burns inside, without mucking about too much with the highlight, midtone, and shadow controls (deadline, remember?)
  • Set Colour Saturation to 1,125, just to make the colours pop a little more together with the tweaked IBL
  • In Render Settings, I scrolled down tot he bottom of the ProRender tab, and clicked Anti-Aliasing.
  • I set my settings to Production in the dropdown and set AA samples to 4 instead of 16. As with any renderer, the higher the AA, the slower the render.
  • I then let the render run overnight, for a 4K final image


That’s pretty much it  – Thank you for reading, and if you have any questions, please don’t hesitate to contact me ☺

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