360 Images with Iray+

Iray+ is a separate add-on to 3ds Max that offer more features than the regular iray rendering engine included for free in every 3ds Max installations. Most importantly, it supports the creation of 360 images. Iray+ requires a compatible NVIDIA graphics card to render images, which makes it much faster than most CPU based rendering engines. We do not recommend this software unless you have a compatible graphic card on your computer system.

Iray+ also comes with an extensive material library aimed at architecture. This makes it easy to apply beautiful materials with photorealistic properties to your model renders.

You can download a free 90 day trial of Iray+ for 3ds Max.

Note: Iray+ 1.2 is a new version or Iray+ that enabled 360 images. We came across some bugs during the rendering process and documented them thoroughly. Be aware that since this is new technology, you may come across some early-adopter issues during the process. We still believe that Iray+ can provide some of the best indirect lighting in the industry and that it is worth the trouble. As time progresses, these early adopter bugs should be ironed out.

In Revit, set you units to feet even if your project is a metric project (this is an Autodesk limitation). Save your Revit file. Then, open a blank file in 3ds Max. Save it immediately into the same directory with an appropriate name.

After this is done, you can link your Revit project. In 3ds Max, make sure that your System Units are in Feet. Go to the Customize tab, click "Unit Setup", then "System Unit Setup" and set the units to feet. After this, you are ready to link the file.

To link the Revit model, click the "3" at the top left and select "Reference", then "Manage Link". Select your original Revit file, then select a camera View and click OK. The default preset "Autodesk Revit - Combine by Revit Materials" should be selected. Click "Attach this file". Once the file is loaded, close the "Manage Links" window.

If 3ds Max offers you to apply an exposure value, select no.

Convert to Iray+ Materials

Save your scene. As soon as you change your rendering engine to Iray+, you will be prompted to convert the scene.

Click on Convert and wait for the process to finish. You will be prompted to change the Iray+ exposure. Click yes, go into the "Settings" tab and and click "Enable Tone mapping". The exposure value will already be set at 14, which is fine if you have a sun in the scene. For interior scenes without a sun light, you can bring the exposure down between 6 and 14.

Test Render and Fix problems

Do a test render to detect any geometry or material anomalies. In our case, we are testing Iray+ 1.2 on launch day, so we encountered some bugs with both geometry and materials. Let's go over both.

Inverted normals on glass geometry

It seems that the 3ds Max linking process or the Iray+ converter inverted the normals of some of the glass materials. This is evident in that some of the windows are fully opaque.

 

To fix this, we binded the file, this removed the dynamic link to Revit, but it is a minor inconvenience. Leaving the file as a link would've simplified the updating process for when the Revit model changes. To bind the file, click the "3" at the top left, "Reference", "Manage Links", and click "Bind" in the "Files" tab.

Once this was done, we selected the glass geometry and applied a "Normal" modifier to it, with none of the options selected. This seems to have fixed the geometry problem, but the glass material is not letting direct light inside the house!

Glass geometry is transparent, but not...

The glass seems to let light inside the house, but not direct light. This is a physically impossible material. It is either due to bad material definition in the default Autodesk glass Revit material, or the Iray+ material converter, or both.

To fix this, we need to dig into the new glass material. Open the Material editor by pressing "M". Use the material picker and click on the glass geometry. If we peek at the material properties, we notice that the transparency is set at 50%. We can change this to a more realistic number, like 0.95 for 95% transparency. Still this does not fix the problem of direct light.

If you scroll down, you will notice the Geometry Opacity is set to 1, which means 100% opaque and 0% transparent. Obviously, this is impossible. We will set the Geometry Opacity to 0.05 (5% opaque), which will equal to 95% transparency. Now when we do a quick test render, everything is fine.

 

The image is dark, so we changed the exposure from 14 to 12. This number is somewhat arbitrary, change the light exposure to make the scene as dark or bright as you want it. Most values should be within 6 to 14, re-render the scene to validate the exposure value.

Render a 360 image

Make sure your camera is at the right height, with no pitch or yaw. It should be looking straight to the horizon, without looking up or down. It should also be about 2-3 feet away from any surrounding walls.

To render a 360 image, press "C" and select the desired camera. Click F10 and go under the "settings" tab. Change the Camera lens to "Spherical". Put "Stereo output" to "ON". You can leave the eye separation (IPD) to the default or make it match the IPD of the GearVR: 0'2 24/32" (70mm).

You will need to render both eyes separately. Select the "Right eye" to start you first image.

To set you render quality or time, go to the Iray+ tab and select a time or a number of passes. We recommend at least 700 passes for an image to be reasonably smooth. The time will vary depending on how good you graphic card is. The render will complete once one of the two conditions is reached.

Go into the "Common" tab and set the image resolution to 4096 by 2048.

You are now ready to press "Render"

Once the first image is done, save it as "Right" press F10, go to the "Settings" tab and select "Left Eye". Render the second eye using the same render settings. Save this new image as "Left".

Upload to InsiteVR

Once you've saved the JPG file, you can upload it to InsiteVR and share your renderings on a regular screen, a cellphone or embed them into your 3D model walkthrough for VR.

You can have a look at the project on InsiteVR with your cellphone or on an internet browser here.

Reference: https://www.lightworkdesign.com/images/support/3dsMaxDocumentation/features/settings.html#Camera

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