Rendering in Revit Architecture 2009 with Mental Ray

With the new release of Revit Architecture 2009 came a lot of excitement, due largely to the inclusion of Mental Images’ Mental Ray in place of AccuRender for the Revit rendering engine. But how does Mental Ray perform in Revit, and what exactly does it add to your workflow.
As an avid 3ds Max user, I was keen to address the question or how Revit’s Mental
Ray compares to that of the one in 3ds Max. So, I did a little testing and can safely say that, in my opinion, it fares very well; it has all the Pro Materials from 3ds Max (so the setting up of objects for rendering is very straight-forward), lights are a breeze, and all the photometric or IES light data contained in your Revit Light will be used in rendering calculations in Revit.
The Mental Ray interface is a lot more streamlined compared to the Max version,
with simpler controls and a more user-friendly, less menu-intensive feel.
Although this does restrict some of the finer settings available in 3ds Max, it makes picking up and producing good quality images - even for the complete beginner - very simple. As a general rule of thumb I’d say that Mental Ray in Revit achieves about 80% of the image quality in 20% of the time you’d expect from 3ds Max.

Getting into the interface


The render dialogue is easy to find and is represented by a teapot icon in the bottom toolbar when in your perspective view.
Once the dialogue window has loaded, first impressions are very good: endless drop
downs and menus within menus are defiantly a thing of the past, with all options sensibly labelled making for quick and easy adjustments.

Even without going under the hood or into any of the custom quality settings good quality renders can quickly be achieved by simply choosing from the listed pre-sets on this screen.

The Quality pre-sets (i.e. those dictating how good your image will look) include options for draft, low, medium, high and best. From what I’ve seen and played with I don’t think you’d want to be showing customers renders with anything less than the medium setting. The draft and low settings are great, though, for quick test renders, making sure that your lighting is correct and ensuring that the overall composition of your image is right before waiting for the higher quality renders.



A nice feature from this dialogue is the ‘region’ tick box, which allows you to specifically render a user-defined area of your scene. This is an excellent time-saver when assigning materials to your design because it allows you to quickly produce renders with the ‘best’ quality setting in order to see how objects are going to look texturedwithout having to wait for your whole image to render.
Looking under the hood of the Quality settings takes you to a customisable screen for tweaking your settings. Again, hats off to Autodesk: these options are extremely easy to use, with a nice interface explaining what each option does and a simple slider adjustment to make any changes. If I had one complaint it would
be that it’s too easy to make changes! There have been a couple of times when I’ve become ‘slider happy’, maxing out all the settings but then realising that I’m going to have to wait a week for the image to render.

For those of you familiar with Mental Ray in 3ds Max and Viz, all the usual options
for Anti-aliasing, Reflections, Shadows etc.
are here, so if you know what you’re doing then you can play to your heart’s content. For the average user, though, I think the ‘high’ and ‘best’ options will provide more than enough realism without having to worry about these settings.

As briefly mentioned earlier, Revit Architecture 2009 now includes the Mental Ray Pro-Materials. For those unaware, the Pro-Material library was officially introduced with 3ds Max 2009 and provides fast access to pre-set materials that
are ready for rendering in Mental Ray. Again the user interface is spot on, with easy-to-use modification options and thumbnails depicting how the material will look when rendered, thus giving you the best possible insight to how your objects will look. The Pro-Material library is extensive and really does make texturing a design very quick and simple.

Materials Library (below)


Render Appearance Library (below)


The realism in any render is usually down to two factors: light and shadows. It’s
incredible how a 3D-looking scene can be made photorealistic with the effective use of lights and subtle inclusion of shadows. As we’ve discussed, setting up lights for rendering is extremely straightforward; all Revit Light data is available to the Mental Ray engine, so if you are using photometric or IES data the lights in your scene can be visualised as they would be in the real world.
Again, lighting settings are pre-set driven in Revit 2009 with 6 available options; 3 for exterior lighting and 3 for interior. Below, we’ve depicted the lighting of a simple room with a large curtain wall and a floor lamp to show the effect of the different pre-sets.

Exterior: Sun only


Exterior:Sun and Artificial


Exterior: Artificial only


Interior: Sun only

The industry feedback we at Jigsaw have received so far is very good, and I’m personally very impressed with the Mental Ray inclusion. Customers I have spoken to have all been blown away with the ease and quality with which renders can be set up.
One firm has even said that they no longer need to outsource their visualisation but instead can save the money and get all their images produced from Revit in-house!

I think it’s great that Autodesk is extending its traditional media and entertainment products into the architectural space. As we all know, average 3D renders are no longer cutting it with customers, so in order to get those bid-winning presentations technology from the film, TV and game industries needs to be utilised. At a time when a growing number of dedicated visualisation firms are being set up, Autodesk’s introduction of Mental Ray into Revit has opened up to its
customers the possibility of good quality, in-house visualisation. Who could ask for more?!