Lighting La Ruelle - Chapter 1 (3ds max & mental ray): Fog/Mist at Nighttime
During this exterior lighting series I will be covering the techniques I used to create various time and weather conditions using 3DS Max and the Mental Ray renderer. I will be concentrating on describing my lighting methods rather than any modelling or texturing that may need to be done. I have created as much of the image as I can in Max; leaving Photoshop 'polish' to a bare minimum to achieve the final result.
For this first chapter, I will be covering setting up a foggy and damp night time atmosphere with the intention of making the viewer climb into the image and want to explore the environment. What's up those stairs? Is there anyone in the houses? What's behind that door? What's the story here? I hope you enjoy reading my tutorial and learn something you can apply to your own work.
Identifying light sources
Here is the raw image (Fig.01).
I've highlighted the possible light sources that can be used. The most obvious of these is the lantern illuminating the street but I also want the moonlight to cascade down the stairs and spill through the archway. There are also the many windows and doors that I can use to add life to the image.
The archway and stairs are central to this image; if lit correctly they can add depth and help to make the viewer want to 'climb' into the image as I described earlier. In contrast with a daylight scene, the shadows in this scene should be very soft so I used MR-Area Omni lights to light the entire scene.
The weather conditions (a foggy evening) also generate their own light so I had to take care not to wash the image out. However I used the fog to my advantage, creating further depth; light disperses through the fog creating a glowing effect, enhancing the mysterious look I wanted to achieve. At this stage, however I needed to concentrate on simply getting the lighting right. I will return to how I created the foggy look later in the tutorial.
Setup draft render
When lighting any image, you can't expect to achieve the final result first time. In anticipation of a lot of 'tweaking', I did many test renders. As this could potentially be very time-consuming, I setup the renderer to a draft setting so it speeded up the render times to a more workable rate. Firstly I assigned Mental Ray as the renderer and used these settings for draft renders (Fig.02).
By base lighting I mean natural lighting; for this scene it is the moon and its bounce light. The moonlight in this image is very important, I used it to help focus the viewer's eye into the centre of the image and help create depth. I didn't want the moon itself to be visible as I thought it would interfere with the composition of the image, so I kept it hidden behind the buildings. I placed a MR-Area Omni light just behind the archway, about halfway up the stairs. I used the attenuation settings to give me more control over the falloff of the light so it starts and ends when I tell it to. You can achieve this control by editing the attenuation settings and adjusting the start and end values.
Here are the settings I used for the moon light (Fig.03).
Here is an image of the placed light (Fig.04).
I also added moon light to the upper right of the image using a MR_Area Spotlight. I gave it a white with a light blue tint and a power of 2.0 I positioned it so it was pointing across the surface of the wall; this also gave me a soft shadow from the roofing tiles and helped to pick out the bump map giving more detail to the image.
Here is the light in the scene (Fig.05).
Here is a render of the moon lighting applied (Fig.06).
As you can see the moonlight cascades down the stairs and through the archway, creating a very soft arched shadow over the cobbled stones. It's a little dark and flat around the front of the buildings, even at night you get some bounce light illuminating the shadowed areas. So I placed another MR_Area Omni light at the front of the scene above the buildings. This will make the detail at the front of the building pop out.
Here are the settings for the Night bounce light (Fig.07).
Here is a render of all the base lighting applied (Fig.08).
The image Is still dark and uninteresting but once I apply the environmental lighting it will create more life in the scene.
Environment lighting was my favourite aspect of this tutorial. For this scene, the most important part of the lighting comes from the street lamp as it serves as a focal point and plays a big part in creating the illusion of a foggy night. Before I placed the light in the lamp itself, I needed to setup the lamp object so it interacted correctly with the light once added. I had to alter some of the settings in the glass geometry of the lamp so it didn't cause any unwanted light interaction. To do this I selected the glass panel object, right clicked and selected 'object properties' from the quad menu. In the window pop-up I needed to de-select 'cast shadows' and 'accept shadows'.
After making these changes, when I placed a light inside the lamp object the glass panels didn't cast shadows and block out the light being cast. The only shadows that should now be cast are from the lamp object onto the walls and floor, but these shadows should be so diffused you will not notice them. I added a MR-Area Omni light in the scene and moved it to sit inside the lamp object, roughly where a light bulb would normally sit.
Here are the settings I used to get the right result (Fig.09).
Here is an image of the placement of the light (Fig.10).
The lamplight is quite an expensive light as it has multiple effects applied to it to obtain the foggy effect. I will revisit this in more detail later on in the tutorial. By 'expensive' I mean it took more time to calculate the render. However as this is the centrepiece of the lighting, I feel it is worth the extra time for a more realistic finish.
Here is a render of what we have now (Fig.11).
Looking at the latest render you can see that it still required more work; there was something missing. The image still looks a little flat and uninteresting: what was missing was life. In order to bring life into the image I needed to apply lighting to the windows and doors. I did this in two ways: (i) by using textures to create a self illuminating material giving the illusion of light being cast from inside and (ii) from physically carving out the geometry and forming 'fake' rooms behind the windows and doors and using a real light to illuminate the scene. This technique also gives us the option to add environmental effects such as Volume lighting; further enhancing the lifelike look I was trying to achieve. As I used both techniques in this tutorial, I will outline them both so I can demonstrate the differences.
Let's start with the doors on the left hand side. Firstly, I needed to cut out the door from the geometry and create a 'fake' room behind it. To do this, I created an open end box which surrounds the doorway, making sure all holes are welded and the geometry was solid. This reduced any lighting anomalies that may occur later on in the render. I wanted the light to come from inside the 'fake' room and spill out onto the cobbled stone road. I only wanted this room to emit a small amount of light as I didn't want it to be too overpowering and draw the viewer's eye away from the archway. For this reason, I rotated the door 10 degrees inwards to allow just enough light to escape the 'fake' room.
Here is an image of the new geometry and the rotated door (Fig.12).
I then place a MR-Area Spotlight in the 'fake' room and positioned it so it was pointing out of the door opening.
Here is an image of the positioned light (Fig.13).
I then edited the attenuation settings to give me control over when the light starts and ends. I decided to use a spotlight for this because I wanted the light to be pointing downwards towards the street. If I were to use an Omni light the light would also go upwards.
Here is an image of the settings I used for this spotlight (Fig.14).
And here is a render of what we now have (Fig.15).
At this stage, I was starting to add more life to the image but it was still missing something so I moved onto the windows. For the windows I again decided to carve out a 'fake' room behind and use a real light to illuminate this area. Using the same techniques for the doors on the left I cut out the windows and created a simple box room. This second 'fake' room also keeps the light from escaping behind the buildings.
Here is an image of the geometry after I've carved the windows out of the building geometry (Fig.16).
Note: I have only cut out the tops of the windows because I wanted to use the self illuminating material to light up the remaining window. This will give the effect of something blocking the window from the inside and help create a more realistic 'fake' room. Also if I cut out the entire window the light that escapes would over-power the image and ruin the look.
To create a self illumination map you need to create a black and white image of the texture, black being not illuminated and white being illuminated. The black and white image is placed in the self illumination slot of the material.
For the real lights I used two MR-Area Omni lights and placed them inside the 'fake' room.
Here are the settings I used (Fig.17).
I used the light from the windows to help define the building on the left and make sure it stands out from the background building.
Here is a render of the image so far (Fig.18).
Here you can see the light creating an outline of the building on the left making it stand out from the background building. Also the variation of colour difference from the self illuminated windows and the real windows gives the impression of an actual room with genuine atmosphere inside.
Once the windows were lit in the foreground, the building above the archway began to lack detail and 'got lost' in comparison with the other buildings in the scene. There is a window to the right of the door. I used the same methods as before and cut out the window and hollowed out a 'fake' room behind, duplicating the same MR-Area Omni light that was used in the other 'fake' rooms. I placed the light behind the window and kept the settings the same.
And here is a render of what we now have (Fig.19).
With the bulk of the lighting complete, it is now time to move on to the weather!
Fog is fairly simple to create and is quite quick to render, nothing needs to be setup in the scene in order to make this work. It's as simple as enabling it in the environment window. Firstly I hit the number key '8' to bring up the Environment Settings tab. I then scrolled down to the Atmosphere settings and clicked 'Add'. This brings up another window with multiple choices of the type of effects you want to activate so I clicked 'Fog' and pressed 'OK'. This enables 'Fog' to be added to the Atmosphere section on the Environment Settings tab. From this tab, I then selected 'Fog' to enable the options to become visible.
Here are the settings I used for the Fog (Fig.20).
The fog provides a layered effect and silhouettes the buildings, helping to maintain the structures even in this dull weather condition.
Here is a render with the fog applied (Fig.21).
Street Lamp Lens Effects
The street lamp is the main focus so this needed to have more than just volume light applied to it. I used some Lens effects to give the impression of a light bulb glaring in the fog, casting shadows in the atmosphere. The final tweak was to make the light in the street lamp give off real characteristics of a light bulb. To get this effect I added Lens Effects to the MR-Omni light. This is done under the Atmosphere & effects tab of the light settings and adding a Lens effect from the add menu, the same way you would add volume lighting. Now that the Lens Effect has been activated on the light we can edit the settings in the Environment and effects window. Here you are presented with multiple options for effects, but for this scene I will only add 'Glow' and 'Ray'
Here are the settings I used for the Glow and Ray effect (Fig.22).
What I felt was lacking from the image at this point, was a bit of bounce light to illuminate the doors and windows. This will add more detail to the image and make the image a lot more interesting. I could add bounce light in the Mental Ray renderer but I wanted a bit more control and to be a bit more artistic with the bounce light rather than leaving it to be mathematically correct. I started with the doors on the left. I added a low intensity MR-Omni Area light with a small attenuation to only affect the nearby geometry. I removed shadows cast so I didn't get any unwanted lighting issues.
Here is an image of the settings used for the bounce light (Fig.23).
With the tweaking completed, it was time for a medium settings render so I could see if there were any errors that needed fixing before taking the plunge and setting up a final settings render.
I set the renderer to medium image precision and medium Final Gather settings. At this point, I still hadn't enabled bounce light as it would have dramatically increased the render times. With the new settings I was able to see any problems that may occur.
Here are the settings for the render (Fig.24).
I was quite happy with the medium render and I couldn't see any major issues. Some colour correction needed to be done in Photoshop but this is normal with any image; it adds that extra bit of polish to the image.
I was now ready to go ahead and set up a high quality render.
Final render setup
The render times for the final render will be quite long, so be prepared to not be able to use your computer for a day depending on how good your PC is.
Here are the settings I used to get the final render (Fig.25).
The size of the image is quite large because the image might be used for printing purposes and the larger the image the better. You should always aim to render your image for printing purposes just in case your image gets accepted into a magazine gallery or art book. You don't want to have to re-render your image at a later stage and re-do any post work that you apply.
So with everything setup it's time to hit that render button for one last time.
Here is the final Image rendered straight out of Mental Ray (Fig.26).
In Photoshop I used 3 adjustment layers to create the final image, namely 'Levels', 'Colour Balance' and 'Photo Filter'
Here are the settings I used for the 3 adjustment layers (Fig.27).
I also used Lens blur to provide Depth of Field. Using a Zdepth render element, I placed this image in the Alpha channel of the PSD. I then selected 'Lens Blur' from the effects menu in Photoshop which adds a little photographic realism to your image. You will notice the highlights on the steps in the background become over exposed and really twinkle with these specular highlights adding to the 'Damp' feel we wish to achieve.
Here are the settings I used for Depth of Field (Fig.28).
Here is the finished product (Fig.29).
I'm quite happy with the end result and I think I achieved what I set out to do. Hopefully it tells a story and makes you want to see what's behind that door or what's on the other side of the archway. Most importantly I hope you were able to follow this tutorial and learn something from it. I actually learned a lot making it and enjoyed myself too. Thanks for reading and happy lighting!