Z-Fighting Issues with Conversion Method v4, No Problems with v3 in Autodesk Viewer

Question

I’m currently working with Autodesk Viewer 7.101.0 and the Model Derivative API for visualizing multiple IFC models, and I've run into a persistent Z-fighting issue.

I’ve used both translation method v3 and v4 to convert the models:

• With conversion method v3, everything renders perfectly, even when elements are close together (like overlapping ceilings or walls from different models).
• With conversion method v4, overlapping elements consistently show Z-fighting issues—flickering, blending, or visual artifacts.

For example, with closely packed ceilings from different IFC layers, I notice flickering or "depth fighting" in v4 when loaded in the Forge Viewer, whereas in v3, these same models display just fine without any visual issues.

• Viewer Version: 7.101.0
• Conversionmethod: Using both v3 and v4.

I’m not applying any transformations or offsets to the models, and I’m just loading them as they come from the conversion process. This is how I load them, and they are visually inconsistent between versions of the conversion:

• v3 models look good without Z-fighting.

• v4 models exhibit noticeable Z-fighting, particularly where objects overlap or are extremely close to each other.

  service.translateObject = async (urn, rootFilename) => {
      const { access_token } = await service.getInternalToken();
  
  
      const jobPayload = {
          input: {
              urn: urn,
              compressedUrn: !!rootFilename, 
              rootFilename: rootFilename 
          },
          output: {
              formats: [
                  {
                      type: 'svf2', 
                      views: ['2d', '3d'], 
                      advanced: {
                          conversionMethod: 'v4' 
                      }
                  }
              ]
          }
      };
  
  
      try {
          const job = await modelDerivativeClient.startJob(jobPayload, {
              accessToken: access_token,
              xAdsForce: true, 
              xAdsConversionMethod: 'v4', 
              xAdsDerivativeFormat: 'latest' 
          });
  
          return job.result;
      } catch (error) {
          console.error('Error iniciando la conversión del modelo:', error);
          throw error;
      }
  };
  

  Is there a specific reason why conversion method v4 causes these Z-fighting problems compared to v3?

  Are there any recommended settings or adjustments I could apply to mitigate this, either during the model conversion or within the Viewer?

I’d be very grateful for any advice or tips from anyone who has faced a similar issue or knows how to tackle this difference between versions.

Thanks!