BIM Element Overlay

BIM Element Overlay

Overview

BIM Element Overlay in OpenSpace helps improve installation planning, coordination, and communication. You'll choose items from the model, such as an HVAC grille, and position them in your jobsite imagery. Overlays can help you better understand spatial relationships and sequencing before work begins, and better coordinate how different systems will be installed around each other, preventing field clashes. Use BIM Element Overlay to align stakeholders, anticipate installation challenges, and improve coordination efforts without switching between multiple platforms.

Permissions

Setting a default model

You can upload multiple models to an OpenSpace site, but in order to take advantage of the underlying AI model that supports improved BIM Element Overlay alignment, you need to choose one model to use. We call this the “default model.” Only Site and Org Admins can select the default model. For best results, choose a model that shows major architectural and structural elements. Note that point cloud files cannot be set as the default model.

Here’s how the BIM Element Overlay tab in Project Settings looks after setting a default model:

How to overlay elements in BIM Compare

• Select at least one BIM element on the model side of BIM Compare, then right click. Options, such as Overlay will then become available:

• To access elements modeled above the ceiling, hide BIM elements such as ceilings using the Hide option.

• To select multiple BIM elements at once, hold Shift while clicking each element, then send them over by hitting O on your keyboard, or right-click and select Overlay.

• Once overlaid, you can navigate to a different frame in the capture—even on a different floor—and the elements will remain visible until you manually clear them. You can clear the selected elements by right clicking on them on the capture side. 
  • Note: Overlay alignment accuracy can vary by frame. BIM Element Overlay is intended as a helpful reference for discussions and decision-making, not as a precision-based QA/QC tool.

Improving alignment with the calibration tool

If the overlay alignment needs improvement: 

• Click the BIM Element Overlay button.
• Select Calibrate and use the position controls to adjust to the desired model position.

Sharing and saving your overlay

• Share with collaborators: Create a BIM Compare Field Note to capture and share the current overlay view with others on your project.
• Return to an overlay later: Create a Saved View to bookmark your overlay configuration for future reference.

FAQ

I tried the calibration tool, but the alignment still isn't as close as I'd like. Why?

If the capture has not gone through AI processing for this feature, the initial BIM Compare alignment may be off noticeably in overlay view. Try using more than three pairs of points to achieve better alignment. If you need additional help, contact your OpenSpace representative or the OpenSpace Support team.

What level of accuracy should I expect from BIM Element Overlay? Is there a defined tolerance range?

Accuracy depends on several conditions. When following capture best practices—sufficient coverage of recognizable visual features, strong lighting conditions, and appropriate default model assignment in Project Settings prior to capture processing—BIM Element Overlay element accuracy relative to real-world location will usually be within 0.24 meters in the X, Y, and Z dimensions, and within 2 degrees of view direction. Examples that fall outside this range typically fail to meet one or more of these conditions.

The overlaid BIM element isn't as close as I'd like to the correct position. Why?

Several factors can impact overlay alignment accuracy:

• A suitable default model was not set prior to capture, so the AI alignment algorithm has not run.
• Capture conditions lack sufficient similarity to the corresponding BIM views, reducing AI algorithm effectiveness.
• Significant elevation changes during the capture (common in civil projects) can negatively affect Z height accuracy in the overlay.

If any of these factors apply, use the manual calibrate tool to improve the alignment accuracy for a specific frame. 

If you have any additional questions please reach out to the OpenSpace Support team at support@openspace.ai.