LOD - the real story.

Well, it's an interesting one! ??

About 15 years ago our small team (then at Graphisoft) "invented" a scale of LOD 100 through LOD 500.

That LOD scale helped describe the geometry needed to run our 4D + 5D software (now called Vico Office).

Over the next 15 years that LOD concept was adopted in various ways across our design and construction industry (image below from Marzia Bolpagni).

Although it was cool to see it adopted - it made us worry a bit.

Here's why...

Our original LOD goal (then Level of Detail) focussed on specifying model geometry.

It did not include many of the other extremely important aspects for planning different BIM uses.

For complete BIM planning there are actually many aspects that need to be considered.

Here are some considerations:

1. Geometry - how complex does the graphical detail need to be?
2. Reliability - how much can you depend on the geometry?
3. Accuracy - to what tolerance is the measurement or representation?
4. Information - what data/parameters/attributes are important?
5. Ex/Inclusions - what special project conditions are there?

Not to mention the additional:

• Specifications
• Responsibilities
• Attachments
• Notes
• Classification
• Checklists
• AND PURPOSE!

WHY do we need this requirement and WHO is going to use the output?

Can LOD really help with ALL of these aspects?:

With so many different requirements it becomes a challenge to effectively capture all of these combinations using a single scale of just 5 numbers (LOD 100 - LOD 500).

The UK even looked at adding a second scale: LOI (Level Of Information). 

However the challenge in creating more special LoX scales is that teams then need to reference new dictionaries in order to communicate.

Marzia Bolpagni shares this with us:

As illustrated in my article "The Many Faces of LOD", despite what most think, LOD is a complex and controversial topic. We need to move away from numbering scales (e.g. 100-500, 1-7 etc) that are open to interpretation. What we really need are requirements that we can automatically verify and validate: only then we are creating something smart!

This is vital - our industry requires more flexible, but structured, requirements that can be automatically checked.

OK, now here's the advert ;)

The good news: there's now a BIM planning tool to specify any combination of the definitions above ...with or without the LOD Numbers! :)