This page provides a step-by-step tutorial on using the Section Box tool in V-Ray for Revit.
In this tutorial we’ll go over how to render section cuts with V-Ray by using the Section Box tool that is built into Revit.
To follow this tutorial, you will need to have the V-Ray for Revit plugin installed.
This tutorial page is a companion that goes with the QuickStart video posted on our YouTube channel and is available here:
To download the files used in this tutorial, please click on the button below. This Revit scene is provided by Karam Baki.
Open the Example Scene
Open the section_cut.rvt project, which you can download trough the link above. In this tutorial, Revit 2017 is being used, however you will be able to use this project with Revit versions 2016 and up.
How to use Section Cut
With the project loaded, open the Render 1 render view in the Project Browser. We want to cut a section through this view to render it.
First, enable the Section Box parameter in Properties.
You will see the Section Box appear. You can use the Controls to drag the Section Box to not be quite so large.
It will be easier is to switch to the Level 2 floor plan view here.
Then right click on Render 1 and choose Show Section Box. Now you have it in a bird’s eye view of that 3d view’s Section Box and you can adjust it accordingly.
Adjust the Section Box to have it intersect the project as you see in the image below, right through about the middle of the building.
Switch back to the Render 01 view to see how the section is looking. We will cut out a little more behind the building and in the foreground until we have the image below.
Let us render now to see what the section cut looks like. Switch to a non-3d view: choose floor plan Level 2 as we did before. In the V-Ray tab, change the View to Render 1. Leave the Quality at Draft and set the Resolution to Crop Region with Printer set at a DPI of 75. Then click Render with V-Ray to see how this section looks.
Using Section Cuts for more efficient renders
Now let’s look at a hidden advantage to using the Section Box in other views. Change to Render 2 and you’ll see an interior view of the building.
In a large project such as this, when you’re rendering interiors, you can use Section Box tool to limit the amount of data that is being sent to V-Ray to render, which makes the rendering more efficient, sometimes even drastically reducing render times. Turn on a Section Box for this view.
Just like before, go to the floor plan view Level 2 and then right click on the Render 2 view, and select Show Section Box.
Here is the room we’d like to render.
Set the Section Box to cut through the room as you see here.
Now to set the section vertically: Click on the Section 1 line itself to select it.
Then right click on the section line and select Go to View.
Right Click on Render 2 and select Show Section Box, and you can click and drag the section to fit just the room that we want, the one with the three designer chairs in it.
Go back to the Render 2 view, and Zoom out with the navigation wheel: it’s just this room that we can see.
Rewind back to the original viewpoint we had, and close the Navigation Wheel, and we’re going to render this.
Set the Current View to Render 2 in the V-Ray tab. Set the Quality to High. You will really see the most time savings with a High quality rendering when you are using the Section Box like we are right now. Now to load the rest of the settings: click on the Settings button.
Click on the Sharing tab and click Load Settings.
Choose the Render2.xml file from the downloaded assets.
Click Import Selected to import the settings into the file.
That brings in settings to use a dome light for the environment lighting, as well as setting the camera exposure. We will go back to a non-perspective view: the Level 2 floor plan for rendering.
On the left side is the project with the section view enabled. On the right side is the same project and view, but without the Section Box enabled.
We are rendering both versions, with and without Section Boxes, and showing them side by side for a comparison of the time savings you can see using this neat workflow.
Render with Section Cut
Render time: 4 min. 37.4 sec.
Render without Section Cut
Render time: 8 min. 2.7 sec.
In the video, you can see that the render on the left with the Section Box enabled, starts the render sooner and actually renders the project a bit faster than the render on the right that does not have the Section Box enabled. Hopefully, you'll find this to be a useful workflow with your own projects.