Rebar Models Poor Performance

Hi Speckle team,

Im working on a speckle model sent from Revit 2020 that has 131.700 RebarGroups and I have notice the following:

  • It is hard to send a hi number of rebars to a Project in the Revit connector, most of the time i get an error. The only solution has been to create branches (Models) and send it by parts. This is really time consuming.

  • Specke viewer showing rebars is really slow. In this Proyect if I try to see all models at once, I Will get chome tab to use more tan 4 GB of RAM, an eventualy the fatal error.
    Viewer - Monamour Rebar - Speckle ¡please try it!

  • If i try to display only some of the models it Will work, but with really bad performance. You cant work with it. (It Will be nice to have the feature of Adding Multiple models at once in the new front end, now you need to add one at a time)
    Viewer - Monamour Rebar - Speckle ¡please try it!

  • Autodesk forge viewer is a lot faster. This is a link of the same model, it can show all rebars an even concrete elements. In speckle i just send rebars. Autodesk Viewer | Free Online File Viewer

Im sorry to keep pushing you so hard, but im anxious of working with speckle in our web app.

Here i let you 2 videos showing performance


Let me know if I can be of any help.

1 Like

@gjordanp, I have already logged rebar performance, and you have reported the issues with shape-constrained rebar to us. They are on the backlog, but I don’t have a timeline for resolving these issues.

Can I make this a public thread so others might offer their +1s? We have a few rebar tickets, but not a lot. Exposure to others might generate a little more interest, which definitely influences prioritisation.

Thank you, @gjordanp, for your detailed feedback and for highlighting the challenges you’ve encountered handling and viewing large quantities of RebarGroups in Speckle.

We’ve carefully reviewed your concerns, and thanks to insights from @Alex and the connectors team, I’d like to outline our approach to addressing the issues you’ve raised:

  1. Optimising Line Rendering: Our current method for rendering lines—using triangles and extensive calculations for variable thickness—is not optimised for the sheer volume of lines present in RebarGroups. We’re actively looking at how to best respond to this use case: see 2
  2. Specialised Rendering for Rebars: The unique challenges posed by RebarGroups necessitate a more specialised approach to rendering. We are exploring methods that simplify line rendering for this specific use case or introduce techniques to manage large datasets efficiently.
  3. Acceleration Structures: To enhance performance across the board, we recognise the need for acceleration structures that quicken line intersection calculations (essentially, what have I clicked on?).
  4. Hardware Considerations: The viewer’s performance can vary significantly based on the GPU. While we aim to optimise Speckle for a wide range of hardware, we also acknowledge the limitations of lower-end GPUs and investigate solutions to mitigate these effects.
  5. Benchmarking Against Autodesk Forge: We note your comparison with Autodesk Forge’s performance. It serves as an important benchmark for us. Was the video recording of both Forge and Speckle viewers with the same model made on the same machine?

Your feedback is crucial for our ongoing development, and we’re grateful for the opportunity to improve Speckle. We’re keen on further discussions and would appreciate any additional insights or suggestions you might have.


Great @jonathon ,

Thanks for taking this into consideration.

  1. Optimizing Line Rendering: In my experience, there is no rebar with variable thickness, so volume should be diameterArea * length.

  2. Specialized Rendering for Rebars: Yes, as I showed you before in another post, Autodesk Forge does not render arcs. I’m not saying this is the way to go, but there is definitely something there.

  3. Hardware Considerations: Yes, I do not have the best GPU, but my PC is really powerful. It has an Intel Core i9 13th generation CPU and 32 GB of RAM.

  4. Benchmarking Against Autodesk Forge: Yes, the video was recorded with the same model on the same machine. Furthermore, the Speckle video was recorded with only some floors of the full model because I couldn’t render the full model. The Forge model also included concrete geometry, whereas the Speckle model didn’t. The model even runs smothly on my cellphone.

I’m really happy to help. I know this is the way to go for my startup. I will be starting to integrate the Speckle viewer soon and wait for rebar improvements.

Thanks for the great work.


Hi @jonathon do you have a roadmap for this?

For now i’m already working with Autodesk Viewer. But im still hoping to change to Speckle.


2024-04-22 11-39-07.mkv (8.6 MB)