[Bug]: "memory access out of bounds" during ifc to frag conversion

[alexberd]

What happened?

I am using the following npm script to convert .ifc to .frag and I am getting the following error when trying convert the ifc of the following element exported from Revit. I am wondering what the error is for the particular elements and if there is any flag to disregard elements which cannot be converted from ifc

web-ifc version wasm file:

https://app.unpkg.com/web-ifc@0.0.74/files/web-ifc-node.wasm

npm error:

RuntimeError: memory access out of bounds
    at wasm://wasm/00505fe2:wasm-function[209]:0x19347
    at wasm://wasm/00505fe2:wasm-function[209]:0x1f112
    at wasm://wasm/00505fe2:wasm-function[209]:0x1f112
    at wasm://wasm/00505fe2:wasm-function[209]:0x1f112
    at wasm://wasm/00505fe2:wasm-function[209]:0x1f112
    at wasm://wasm/00505fe2:wasm-function[209]:0x1f112
    at wasm://wasm/00505fe2:wasm-function[209]:0x1f112
    at wasm://wasm/00505fe2:wasm-function[209]:0x1f112
    at wasm://wasm/00505fe2:wasm-function[209]:0x1f112
    at wasm://wasm/00505fe2:wasm-function[209]:0x1f112

element visual geometry:

ifc file:
https://we.tl/t-9xSQVEEbXZ

npm script:

import fs from "node:fs/promises";
import path from "node:path";
import process from "node:process";
import * as FRAGS from "@thatopen/fragments";

async function main() {
  const [inputIfc, outputFrag] = process.argv.slice(2);

  if (!inputIfc || !outputFrag) {
    console.log("Usage: node convert-ifc-to-frag.mjs input.ifc output.frag");
    process.exit(1);
  }

  const ifcBytes = new Uint8Array(await fs.readFile(inputIfc));

  const importer = new FRAGS.IfcImporter();
 
  const wasmDir = path.resolve("public", "web-ifc-074") + path.sep;
  importer.wasm = { absolute: true, path: wasmDir };

  console.log(`Converting: ${path.basename(inputIfc)} (${(ifcBytes.byteLength / 1024 / 1024).toFixed(1)} MB)`);
  
  const fragBuffer = await importer.process({
    bytes: ifcBytes,
    progressCallback: (progress) => {
      // progress is typically 0..1
      const pct = Math.round(progress * 100);
      process.stdout.write(`\rProgress: ${pct}%   `);
    },
  });

  process.stdout.write("\n");
  await fs.writeFile(outputFrag, Buffer.from(new Uint8Array(fragBuffer)));

  console.log(`Saved: ${outputFrag}`);
}

main().catch((e) => {
  console.error(e);
  process.exit(1);
});

FOR THE ABOVE SCRIPT TO WORK I HAVE PLACED web-ifc-node.wasm AT THE FOLLOWING PATH:
MYPROJECT\public\web-ifc-074\web-ifc-node.wasm

Version

0.0.72 & 0.0.74

What browsers are you seeing the problem on?

No response

Relevant log output

RuntimeError: memory access out of bounds
    at wasm://wasm/00505fe2:wasm-function[209]:0x19347
    at wasm://wasm/00505fe2:wasm-function[209]:0x1f112
    at wasm://wasm/00505fe2:wasm-function[209]:0x1f112
    at wasm://wasm/00505fe2:wasm-function[209]:0x1f112
    at wasm://wasm/00505fe2:wasm-function[209]:0x1f112
    at wasm://wasm/00505fe2:wasm-function[209]:0x1f112
    at wasm://wasm/00505fe2:wasm-function[209]:0x1f112
    at wasm://wasm/00505fe2:wasm-function[209]:0x1f112
    at wasm://wasm/00505fe2:wasm-function[209]:0x1f112
    at wasm://wasm/00505fe2:wasm-function[209]:0x1f112

Anything else?

No response

[MiguelG97]

@alexberd The WeTransfer link has expired. Would you mind providing an updated link? Thanks!

[alexberd]

@MiguelG97 - Please, see the following updated IFC link.
https://we.tl/t-OQPoJInmLf
Any help will be really appreciated.

[beachtom]

There is something recursive in the geometry in this model that the library doesn't like. We've seen this with a handful of models but haven't been able to fix it yet, but it is a known issue. It's not something you are doing wrong. If you are exporting from revit - can you try in IFC4 that may well fix it

[alexberd]

@beachtom - Many thanks for your comment!
I also tried exporting IFC4x3 from Revit and got the same error message, please refer to the following IFC model:
https://we.tl/t-scgq7Iyvmi

We are trying to integrated engine components to a Revit plugin process and unfortunately we depend on Revit IFC exporting procedures. I am wondering if there is any history about this error (you mentioned it is known issue) or any more detailed explanation to what causes this issue to report to Autodesk Forums?

[QuimMoya]

The problem with this model is the way information is structured in the IFC file.

There is a recursive IFCBOOLEANRESULT that repeats hundreds of times for a single object. This overflows the recursive loading mechanism.

A solution for this is possible but requires some time and effort

You can try to export this figure as a single brep.

[alexberd]

@QuimMoya - Many thanks for your advice.
Is there any way to avoid the error and continue parsing the rest of the elements? Currently the conversion process stops by the above errors.
Also, is it possible to log the problematic element somewhere for the user to know that it has been excluded from the conversion?

[QuimMoya]

The object causing the crash is #8943.

However, even if you remove it, there are other massive boolean operations that cause other problems.

I think we must develop a solution for massive boolean operations, but it will take some time.

[MiguelG97]

@alexberd Have you succeeded in opening the IFC file in other IFC viewers?
Both OpenIfcViewer and Speckle (which uses IfcOpenShell library) get stuck while loading the file.

Similar situation occurs with other online viewers. They fail to parse the file.

[MiguelG97]

@QuimMoya - Many thanks for your advice. Is there any way to avoid the error and continue parsing the rest of the elements? Currently the conversion process stops by the above errors. Also, is it possible to log the problematic element somewhere for the user to know that it has been excluded from the conversion?

@alexberd I recommend using this online service to validate the syntax, IFC schema, and rules of IFC files: https://validate.buildingsmart.org/dashboard
In this particular case, there are 682 errors across various IfcBooleanResult entities.
cc: @beachtom @QuimMoya

This might be something worth reporting directly on the Autodesk forum!

[alexberd]

@MiguelG97 - thanks, your response was really helpful.

I can confirm this IFC file cannot be opened in Open IFC Viewer, and it also fails to import using Speckle’s IFC import.
However, the same IFC opens completely and normally in Revit (no missing elements, no warnings), so the file appears to be valid and readable in Revit.

I’m also planning to post this on the Autodesk forums to get their input from the Revit side.

Question

Are there any flags / settings available when running web-ifc (WASM) that can help avoid errors like this?

Since the issue seems related to a maximum recursion depth limit, it feels like the parser might be getting stuck in a recursive loop. If parsing could continue, it might be able to move past the problematic section and still process the remaining elements in the file.

Desired behavior

Ideally, it would be great to have a way to:

• skip or ignore problematic elements during parsing (especially for large IFC files), and

• continue parsing the rest of the model instead of failing completely.

Many thanks!

[alexberd]

I have posted the issue regarding Building Smart Validation to Revit IFC and I have received the following response.

We recognize that Revit files won't all pass the current buildingSMART validation tests, and have items we are working on to address that.

In this particular case, though, given what you've shared, this seems like an issue with the validation service and should be reported to the buildingSMART team.

Issue for Future Reference:
Autodesk/revit-ifc#947