AnsweredAssumed Answered

How to make a fair comparison between MBD and 2D drawings

Question asked by Alessandro Tornincasa on May 14, 2016
Latest reply on May 23, 2016 by Casey Gorman

When you read MBD whitepapers, you always find sentences like this "MBD is a cost-effective tool because it eliminates the time to create and mantain drawings".

 

It's quite intuitive to understand time savings that are consequent to not creating drawings, but it's not so immediate to understand why you would save time without the need to mantain drawings.

I found hard to understand this concept because I was keeping on associating MBD to 3D PDF.

This was my scenario, I was thinking about a part that was produced internally in the company:

- Normally, when you make changes to a 3d model, the 2D drawing will update automatically and you will have to manage issues by dealing with disconnected dimensions or new dimensions to apply

- Suppose you created a 3D PDF and you made a substantial change to your model. The process would be:

1) update DimXpert dimensioning of your manufacturing features (many features will go underdefined or some will require new dimensions)

2) re-publish 3D PDF

If you think of it this way it does seem that there's no time saving, but rather more time for the same process.

 

The big mistake here is the equation MBD = 3D PDF.

MBD is a process involving the whole company, and this idea should be kept separate by the set of tools that are supplied by the CAD vendor to go drawingless in SOLIDWORKS MBD.

 

3D PDF is just one of the design deliverables but think about the other design deliverables you can supply (native 3D model with or without PMI, eDrawing, 3D PDF, etc.).

If we had to make an apple-to apple comparison we would follow this table:

 

Approaches

2D drawing approach

MBD approach

3D deliverables

3D models

3D models + PMI

2D deliverables

2D native drawings

Saved

2D PDF

3D PDF

 

So in my case, since part was produced internally my design deliverable would be in MBD approach "saved": once I fix my dimxpert dimensions I'm making my part available to the whole company in two ways

1) Native SOLIDWORKS 3D file opened with SOLIDWORKS

Remember that new in SOLIDWORKS 2016 is the ability to see previously created 3D views in "ready only mode", so even if don't have a SOLIDWORKS MBD license on your machine you can access those 3D views.

 

Cattura.PNG

2) Native SOLIDWORKS 3D file opened with eDrawings

New in SOLIDWORKS 2015 and 2016 is the ability to access 3D views from eDrawings for both parts and assemblies. Anyone in the company (even workshop people who don't have a SOLIDWORKS icense) can access 3D PMI data.

Here's a demonstration:

eDrawings and MBD - YouTube

 

So we have time savings, think about the fact that native drawings update automatically upon 3D model changes, but in reality, things are more complicated due to separate documents adding complexity:

- Some companies choose to break the link between 3D model and 2D drawings to avoid unintentional drawing changes

- Some 2D drawings could have lost their original associative 3D models

- Some 2D drawings may have different access rights from 3D models

 

There are of course update issues when you change a part: some are applicable to both approaches, while some are unique to 2D drawings such as sheet zoning and view placement.

 

So:

1.    It’s unfair to compare 2D native drawings with 3D PDF.

2.    Native SW MBD files are always the best if collaborators are able to consume.

3.    3D PDF is just one of the possible design deliverable and it's simply a neutral format more widely acceptable, just like 2D PDF of native drawings.

 

Alex

Outcomes