CAD Viewer performance lag with large assemblies in SAP PLM 2020 DMS integration

PLM SAP PLM
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1

Viewing large CAD assemblies in SAP PLM 2020’s integrated CAD Viewer is causing significant performance issues. When engineers open assemblies with 500+ components, the viewer takes 3-5 minutes to load, and navigation is extremely sluggish. This is impacting our design review process and causing major delays.

We’ve noticed the lag is worse for assemblies with complex geometry and multiple subassemblies. Smaller parts (under 100 components) load fine. I’m looking for guidance on assembly file optimization, viewer cache configuration, and whether lightweight file formats could help. Our CAD files are stored in DMS and linked to engineering BOMs. Has anyone successfully optimized the CAD Viewer for large assembly performance?

2

We haven’t configured any pre-conversion. How would that work with our DMS integration? Our CAD files are checked into DMS by designers throughout the day, and we need viewers to see the latest versions. Would pre-conversion cause version synchronization issues?

3

Your issue is likely related to how the assemblies are being converted for web viewing. SAP PLM 2020 converts native CAD formats to a viewer-compatible format on-the-fly. For large assemblies, this conversion is expensive. Consider implementing pre-conversion jobs that run overnight to generate lightweight representations. Also, check if your CAD files are using external references - these significantly slow down loading as each reference needs to be resolved and loaded separately. Consolidating external references into the main assembly file can help, though it increases file size.

4

Another factor is network bandwidth. Large assembly data is transferred from the server to the browser, and if you’re on a slow network, this creates bottlenecks. Check if your SAP PLM server is configured to use compression for viewer data transmission. This is in the ICM parameters - look for icm/HTTP/compression settings. Enabling gzip compression can reduce data transfer by 40-50%.

5

Pre-conversion can work with DMS if you set up proper triggers. Configure a background job that monitors DMS check-ins and automatically converts new CAD versions to lightweight formats. The key is using JT or 3D PDF formats which are optimized for viewing but maintain enough detail for review purposes. These formats load 60-70% faster than converting native CAD on-the-fly. You’ll need to configure the conversion service in transaction CVADMIN and set up event-based triggers in DMS to call the conversion automatically.

6

Let me address all three focus areas comprehensively to resolve your performance issues.

Assembly File Optimization: The root cause is likely unoptimized assembly structure. Implement these strategies:

  1. Simplification Rules: Configure assembly simplification in CAD integration settings. Create rules that automatically suppress internal components, fasteners, and non-visible parts during viewer loading. In IMG: PLM → CAD Integration → Assembly Processing → Define Simplification Rules. Set thresholds - assemblies over 300 components should use simplified representations.

  2. Structure Optimization: Work with your design team to restructure large assemblies using subassembly references rather than flattened structures. The viewer handles hierarchical assemblies much better. A 500-component flat assembly should be reorganized into 5-10 subassemblies of 50-100 components each.

  3. Geometry Reduction: Implement LOD (Level of Detail) configurations. Configure three detail levels:

    • Level 1 (initial load): Bounding boxes only - loads in seconds
    • Level 2 (navigation): Simplified geometry - adequate for spatial review
    • Level 3 (detailed review): Full geometry - loaded on-demand for specific components

Viewer Cache Configuration: Your cache settings need optimization at multiple layers:

  1. Server-Side Cache: In transaction SMICM, configure ICM cache parameters:

    • icm/HTTP/file_access_info = maximum file size for caching
    • Set to 100MB to cache converted viewer files
    • Configure cache directory with at least 50GB space

  2. Application Cache: In SAP PLM configuration (transaction SPRO):

    • Navigate to PLM → Document Management → Viewer Settings
    • Set cache expiration to 24 hours for converted files
    • Enable persistent cache to survive server restarts
    • Configure cache cleanup job to run weekly, removing files older than 30 days

  3. Browser Cache: Deploy these settings via group policy:

    • Enable browser disk cache (minimum 1GB)
    • Configure cache headers in ICM to mark viewer assets as cacheable
    • Set max-age to 86400 seconds for static viewer resources

Lightweight File Formats: Implement a multi-format strategy:

  1. JT Format Implementation: JT (Jupiter Tessellation) is optimal for large assemblies:

    • Configure JT as primary viewer format in CAD integration settings
    • JT supports progressive loading - envelope geometry loads first, details stream afterward
    • Set up automatic JT generation on CAD file check-in using DMS workflow
    • JT files are typically 70-80% smaller than native CAD formats

  2. 3D PDF Alternative: For review workflows requiring annotations:

    • Generate 3D PDF alongside JT for assemblies requiring markup
    • Configure dual-format generation in conversion settings
    • 3D PDF integrates better with approval workflows

  3. Conversion Service Configuration: Set up the conversion service properly:

    • Transaction: CVADMIN (Conversion Administration)
    • Configure conversion profiles for different assembly sizes
    • Small assemblies (<100 parts): Real-time conversion acceptable
    • Medium assemblies (100-300 parts): Queue-based conversion with 5-minute SLA
    • Large assemblies (>300 parts): Batch conversion overnight, JT format mandatory

Implementation Roadmap: Week 1: Configure server and browser caching, enable compression - expect 30-40% improvement

Week 2: Implement JT format conversion for new check-ins - expect additional 40-50% improvement

Week 3: Apply simplification rules and LOD configuration - final 20-30% improvement

Week 4: Restructure existing large assemblies (engineering effort required)

Monitoring: Set up performance monitoring in transaction ST03N to track viewer response times. Target metrics:

  • Initial load time for 500-component assembly: Under 30 seconds
  • Navigation response: Under 2 seconds for rotate/zoom
  • Component selection: Under 1 second

If you implement all three areas, you should see overall performance improvement of 80-85% for large assembly viewing. The combination of proper caching, lightweight formats, and assembly optimization is essential - no single approach alone will fully resolve the issue.

7

Don’t overlook the client-side configuration. The CAD Viewer performance is heavily dependent on the user’s browser and graphics capabilities. Ensure users have hardware acceleration enabled in their browsers and that your organization’s graphics drivers are up to date. Also, the viewer has a level-of-detail (LOD) setting that controls geometry complexity. Reducing the LOD for initial loading can dramatically improve performance - users can then increase detail for specific components they need to inspect closely.