3DS max for those who don’t know (especially when combined with the VRay plugin) is considered the gold standard of professional rendering software. This is because its flexibility, options and power surpass most internal or cloud rendering engines used in BIM software. In particular it outputs images that are perfect for post production outputting reflection and refraction etc as required.
Companies that use Revit often receive as part of their licence deal access to 3ds Max which staff either don’t use because they are unaware of its availability or are intimidated by its fearsome reputation as being complicated, hard to use and demanding of computing power. This complexity myth is further perpetuated by many 3DS Max courses aimed primarily at animators and which focus on elements not relevant to rendering BIM models. The reality is that you really only need to know a very tiny part of 3DS Max for rendering and it’s easy to import almost any BIM software or project into Max. You can also use workflow methods to design your model for efficiency and avoid the drain on computing power.
In the below tutorial we’re going to learn the following:
- How to export a model from Revit
- How to link the exported file
- How to set up lighting
- How to complete an initial test render
- How to complete a final render
Exporting Your Revit File:
There are 3 main ways to export models from Revit into 3ds Max Design. You can export the project natively as a Revit file, a 3D DWG file or as an FBX. Although it is possible to import a Revit file natively straight into max it tends to be better to do so with smaller simple models. With a larger file its gets clunky to use. If the file has references it will add to its ‘heaviness’ also and additional files will have to be imported separately.
Before exporting you need to open a 3D View in Revit in order to export the 3d geometry. The objects that will be exported are the ones that are visible in the view only. The Visibility/Graphics Overrides panel can be used to select the objects you want to export in 3ds Max.
Differences between DWG and FBX file formats:
The main difference between the 2 file formats is that the FBX format exports the 3D geometry with materials, lights and cameras baked in, and gives you the possibility to organize the objects by their family names, types or categories. The DWG file format does not export lights and materials but gives you the possibility to organize the geometry by layers. My favourite method for large files therefore is exporting the Revit model as an FBX file.
Importing vs. Linking files in 3DsMax Design
In 3ds Max you have two options: you can import the file or you can link it. By importing an FBX or a DWG you get the objects in Max but you break the connection between AutoCAD or Revit. This means that if changes are made in AutoCad or Revit you won’t be able to update the scene and must reimport the file. By linking a file in 3ds Max you have the possibility to start working with a project before the final design is approved. You can modify the geometry surfaces and change materials but you cannot delete objects that are linked.
3ds Max Design 2013 gives us the possibility to link directly a RVT or DWG file format.
In 3dsMax click: > Import > Link Revit
Before linking the file you can choose how to organize and combine the geometry in Max. The presets are:
Combine By Revit Material
Objects, with the same material in Revit, are combined in a single object in 3ds Max.
Combine By Revit Category
Combines objects such as Walls, Windows, Doors etc. in a single object.
Combine By Family Type
Every family with all the materials and components included will be imported as a single object in Max. The different materials of the family will be combined in a Multi/Sub-Object material
As One Object
In this option all objects are combined into a single object in 3Ds Max, with one large Multi/Sub-Object material.
Do Not Combine Entities
In this option every single object in Revit will be imported as a single object in Max. The advantage of combining the objects by materials is that the 3ds Max scene contains few objects and materials, which will increase the performance of the program. The main disadvantage is that other family parts will be included in the one object that shares the same material. This may make it difficult to change the scene (for example the wooden part of a chair will be combined in a same object with the wooden floor).
Not combining the geometry will allow you to freely modify every single element but the large amount of objects may overload the scene. I prefer to combine the objects by family type because it is easy to select and transform complex families (doors, windows with different materials etc).
By clicking “Modify…” it is important to activate “Keep 3ds Max scene materials parameters on reload” and “Keep 3ds Max scene materials assignments on reload” so that every time a change in materials is made in Max it will be preserved after the update from Revit.
Material Retention From Revit:
Although the FBX format retains the materials assignments you made in Revit, I would recommend at least assigning a new glass material in Max. When you import by material the FBX file color codes your model so that everything that’s for example ‘frosted glass’ in Revit with one click can be changed to ‘translucent glass’ in max. It’s pretty easy to replace or adjust materials. With this in mind let’s take a more detailed look at the import methods below:
Remember to set up the FBX file as a reference file in max so that each time your Revit model changes, you can save over the old FBX file and max will update accordingly. Assigning materials in 3Ds Max will be discussed separately but is pretty easy to do.
Adding and Adjusting the Daylight System:
The daylight set up will be imported from Revit however if you want to remove or adjust it, you can do so by following the steps below.
Remove & Add New Daylight System:
Go to the Create panel and activate Systems. On the Object Type rollout, click the Daylight button to activate it. 3ds Max will display a dialog that asks if you want to add a Logarithmic exposure control to the scene. Click Yes and add the exposure control. Drag in an empty area of the Perspective viewport. A compass rose will appear. Release the mouse. In either a perspective or plan view, drag to set the height of the Daylight light and click to complete the creation of the new Daylight system. With the Daylight light still selected, go to the Modify panel. On the Daylight Parameters rollout, change the Sunlight type to mr Sun and the Skylight type to mr Sky. When you choose mr Sky, 3ds Max displays a dialog that asks if you want to add a mr Physical Sky environment map. Click Yes to accept the environment map creation and dismiss the dialog.
Modify a Daylight System:
On the Daylight Parameters rollout, in the Position group, click Setup. 3ds Max will shift to the Motion panel and display a Control Parameters rollout. On the Control Parameters rollout, in the Time group, change the Hours value to 16 or whatever time you want. In the Location group, click Get Location. 3ds Max opens a Geographic Location dialog. Use the City list or a map to choose your present location, and then click OK. 3ds Max changes the orientation of the compass to point to the north you entered.
Preparing the Scene Before Rendering
3ds Max gives us the possibility to visualize materials, lights and shadows with a realistic view in the viewport, which gives a preview of the render and allows you to spot any problems.
To activate the realistic viewport shader you have to click:
Realistic > Lights and Shadows > Illuminate with scene lights + Shadow + Ambient Occlusion
After activating the realistic viewport with the scene lights on, you may notice that the scene is burned out with sunlight. You can adjust this by going to:
Rendering > Environment
Exposure Control > mr Photometric Exposure Control
Exposure controls allows you to adjust the output levels and color range of a rendering, as if you were adjusting film exposure. The “mr Photographic Exposure Control” lets you modify rendered output with camera-like controls; either a general exposure value or specific shutter speed, aperture, and film speed settings. It also gives you image-control settings with values for highlights, midtones, and shadows. It’s intended for high-dynamic-range scenes rendered with the mental ray renderer. Depending on the lighting (daytime or night) and scene (interior or exterior), you have to adjust the Exposure Value to have an optimal rendering. Under Exposure Preset: you can choose the EV-values you need for your scene.
It is typical for architectural photography that vertical segments are always parallel to each other. To control the deformation of the camera lens due to the perspective view you can use a modifier called Camera Correction and apply it to the selected camera. It can be found under:
Modifiers > Cameras > Camera Correction
Test renderings should be as fast as possible as they are performed only to test the lights, materials and geometry are working fine. You have to keep the render time smaller than 5 min. By reducing the Output Size of the rendering by 320 x 240 pxl or leaving it by default to 640 x 480 pxl you ensure that the render time won’t take long.
While testing the lights and camera position, the materials are not that important. 3ds Max gives us the possibility to override every scene material with a single material. You can find it in the Render Setup window > In the Processing Tab > Material Override.
The Render Frame Window also contains the sliders which control the precision of the Image, Reflection, Refraction and Soft Shadows. By reducing the Anti-Aliasing the render will be more pixelated and if you reduce the Reflection precision, the quality of the reflections will be poor, but this will save a lot of time if there are many glossy objects in the scene. By reducing the Soft-Shadow precision, the shadows will appear grainy.
Below we will discuss some of the settings and options you can use to achieve a high quality image. 3Ds Max comes with standard renderings presets (found on the lower left hand corner of the rendering setup dialog box) and its definitely recommended to use one of these for a beginner. You can adjust the options listed below and then create a new rendering template which you can then save for future use .
Increase the Render Output Size in order to have a better Image quality. Use the Print Size Assistant to calculate how big the render resolution should be, if printed in different print qualities such as 75, 150 or 300 dpi.
Rendering > Print Size Assistant…
Increase Final Gather
By increasing the final gather precision you can achieve a better quality of indirect illumination but the time will incrementally grow in proportion. In order to avoid this you can use low precision. By increasing the final gather Bounces you can also get more indirect illumination details in parts, which are hard to reach by the light. For exterior renderings you can increase it up to 2 bounces just in case you need some extra detail.
Add Ambient Occlusion to the Materials
Ambient Occlusion is a method for emulating the look of true global illumination using shaders. By activating the Ambient Occlusion of the materials you get more details over edges and the rendering looks more realistic in a short amount of time. You can find the Ambient Occlusion option in the material properties under the Special Effects rollout. One important Ambient Occlusion control is adjusting the distance that controls how far it occludes geometry.
Activate Global Illumination
For Interior scenes it is recommended to activate global illumination. By this process the light source shoots photons that bounce in the geometry and transport light and color. To activate the global illumination go to: Render Setup > Indirect Illumination tab > Global Illumination (GI)
Generating Render Elements
Rendering elements lets you separate various types of information from the rendered output into individual image files. This can be very useful when you work with Photoshop in your post-production of the rendering.
Below we will discuss some of the most useful and common render elements to include in your rendering. In the render setup dialog box you can simply add them to be included with each rendering completed. These elements mimic the effects you would employ in photography to achieve high quality images.
Material ID Render Element:
This element renders the material ID information assigned to an object. This information is useful when you are making selections in image-processing or special-effects applications, such as Photoshop allowing you to select all of the objects with the assigned material ID. The material ID corresponds to the value you set for the material with the material ID channel. Any given material ID will always be represented by the same color. The correlation between a specific material ID and a specific color is the same.
Matte Render Element:
Renders a matte mask, based on selected objects.
MR Shader Render Element:
This element outputs the raw contribution of any mental ray shader in the scene with a map to achieve an Ambient Occlusion pass of the rendering. At the post-production phase you can use Photoshop’s Multiply blending mode to blend this element with the rendering. The Multiply blend mode will overlay just the black pixels, and the white values will be transparent.
This simply captures the reflections in the rendering. This allows you to adjust your reflections easily in a post-production making them stronger or reducing them as is required.
Refraction Render Element:
This pass captures refractions in the rendering allowing you to control the appearance of materials like glass easier.
Z-Depth Render Element:
This creates a grayscale image between the nearest and the farthest object from the camera. The nearest objects appear in white, and the depth of the scene in black. Intermediate objects are in gray, the darker the deeper the object is, within the view. Essentially it creates a fog depth.
Run the Final Render
Having adjusted the precision and set the image output to the size you require, with whatever render elements you prefer (or the preset of your choice activated) you are ready to render your final image. Click on the teapot render button and watch your rendering unfold in the preview window.
Step 1 – Create a perspective image in Revit
- Go to a plan view
- Select the camera tool under the 3d view tab
- Place camera on plan and set view angle
Step 2 – Set the image quality in Revit
- Under the view tabs select the render tool
- Set the sun angle ¨lighting¨ exposure and image quality
Step 3 – Export the image as an FBX
Step 4 – Import the image in 3dsMax
- Under the main 3ds Max tab
- Click import then select your FBX file
Step 5 – Render the View
- Once you have imported the file you should see the entire building in the window space
- To go to the view you want to render type the letter “C” and it will either go to the camera view you have imported or if you have multiple cameras set up in the file it will give you a list to select from.
- Under the tab bar select render set up (teapot with properties icon)
- In this window you can edit the size and quality of the image as well as the global illumination for interior renderings.
- It is a good idea to edit the sampling quality under the Renderer tab similar to antialiasing in Revit it will give you a higher quality image with less pixilation
Step 6 – Render
- Once you have customized your image render quality you can select the render button
- Image should start rendering