Summary
Some PDF plans, especially those exported from Autodesk Revit, may appear slow or lag when opened in Cubit Estimating. This article explains why this happens and how you can optimise these files to improve performance.
Why PDF Plans Can Be Slow
Vector PDF plans contain linework, shapes, and text that must be redrawn each time you zoom or move around the plan in the Viewport.
When a PDF includes a very large number of these elements — often hundreds of thousands — it can cause delays or lag, even on high-performance systems.
This issue can also appear when viewing the same file in Adobe Acrobat or Microsoft Edge, which means the problem is with the PDF’s complexity rather than Cubit itself.
Common causes include:
High object counts (e.g., large architectural or mechanical layouts)
Duplicate geometry within the drawing
Exports made using non-optimised PDF printers or settings
Where These PDFs Come From
Many design teams use DiRoots ProSheets, a Revit add-in for exporting plans.
By default, ProSheets uses its own virtual printer — diroots.prosheets — which is based on PDF24/Ghostscript.
This method can produce very detailed, layered PDFs that are much heavier than files exported using Revit’s built-in PDF engine.
If your plans were created using DiRoots ProSheets, you may notice this behaviour.
You can learn more about ProSheets export options here:
👉 DiRoots ProSheets – Formats Tab
How to Check File Complexity
You can estimate how complex a PDF is using a free tool like Inkscape:
Open the PDF in Inkscape.
Press Ctrl+A to select everything on the page.
Look at the bottom of the window — it will show how many objects are selected.
If the plan contains more than 50,000 objects, performance may be affected.
Files with over 200,000 objects are considered very complex and will likely render slowly.
Ways to Improve Performance
Option 1: Import as Raster (Quick Fix)
If a PDF is slow to navigate, import it into Cubit Estimating as a Raster plan.
This converts the drawing into an image, removing the need for Cubit to process every line and object.
To import as Raster:
In Cubit, open your job and go to the Plans tab.
Click Import Plan.
Under File Type, select Rasterised PDF.
Choose your plan and click Open.
This option provides the fastest performance, especially for large or detailed drawings.
Option 2: Optimise the PDF File (Recommended)
If you prefer to keep using vector plans, you can optimise them using one of the following methods.
A. Use Revit’s Native PDF Engine
If you’re exporting from Autodesk Revit, try using Revit’s built-in PDF exporter instead of DiRoots ProSheets.
In Revit, go to File → Export → PDF.
In ProSheets, open Formats → PDF Settings.
If available, select Use Revit PDF Engine.
Export the plan again.
Using Revit’s own export engine usually produces smaller, cleaner PDF files that perform better in Cubit.
B. Save an Optimised File in Adobe Acrobat
If you have Adobe Acrobat Pro, you can reduce file size and complexity without changing the plan layout.
Open the PDF in Adobe Acrobat Pro.
Go to File → Save as Other → Optimised PDF.
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Tick the following options:
Discard hidden layer content
Flatten form fields
Remove duplicate items
Optimise PDF structure
Save the file with a new name (for example, Optimised_Floorplan.pdf).
This process removes unnecessary data and improves rendering speed.
C. Ask the Designer to Re-Export the PDF
If you regularly receive plans from an architect or design consultant, ask them to:
Use Revit’s native PDF exporter if possible.
Avoid extremely large page sizes (such as A0).
Limit unnecessary detail or repeated elements in furniture or 3D views.
Agreeing on consistent export settings will help keep future PDFs efficient and easier to work with.
Best Practices
To help avoid slow plans in the future:
Request vector exports directly from Revit, not converted from raster.
Limit export resolution to what’s needed for measurement (typically 300 DPI).
Use Raster import for large or external plans when vector data isn’t required.
Optimise or compress any PDF larger than about 20 MB before importing.
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