LOD – The Conversation Continues

I recently had a conversation with an Autodesk BIM PRoduct Manager about BIM and they expressed a desire to have the industry define the Level of Detail (LOD) that goes into a model by the specific trades. He expressed that who does what, when and to what level is still not fully defined as an industry standard.

This conversation has been going on for some time.

He said he thought it might come down to a level of trust. That disciplines will not or cannot trust the data in a model provided by others. I share that concern.

Is it time to start trusting out design partners? or is it that each discipline defines the model data at a level the serves their purpose. Is this just the same grand argument that has haunted CAD forever… that each discipline put into the design files/model what they need to have included to get their job done. They are not going to do other disciplines/firms work.

This has been evident in CAD for a long time. No one wants to add a line or layer to make another persons job easier. They will do when pushed, but not without it defined somewhere in a standard or project guideline.

Can we get past this? Can each discipline understand at the uber collaboration level that they are all in it together. Some firms do this, but not all. Let’s keep the design flow in tact and continue to seek the grand vision of BIM – one model from design inception to construction completion and on to owner/operator use.

The Fear of Over-Modeling – Part 3

Moving to the exact definitions of what goes in where and when, lets take a look at an example Level of Detail (or Development) doc that shows what you need to define.

LOD_Example

Click on this to open it.

You will see that we have the Element type followed by columns for the Level of Detail by Phase (Conceptual thru CA).

Taking the first line – Walls – we see that in the conceptual phase we add detail at the 300 level.  Looking at the Categories doc from the last post we find that 300 is “Out of the box content”.  So you would add walls using OOTB content until you get to DD phase or beyond, where you would go back and create custom content as outlined under Category 400.

Moving down to Clerestory elements for the next example.  It uses 200 (fake content) and then moves to 300 ans then to 400 in CD phase and allows for manufacturing content (500) if desired.

So creating a list of all the content that might be in a model and then assigning a value to that content at a specific phase can help your team know what to do when.  The only thing left is to define Who controls that element.

The Fear of Over-Modeling – Part Two

Last time we discussed the concerns of some to avoid putting too much in the Revit/BIM model. This concern can cause people to include too little and some to include too much.  Defining the exact amount of data may fall into line with the kind of industry you work in or the kind of facility/building you are designing.  It is not an easy definition. It is not a one size fits all BIM World.

In this post I will share some definitions that I have seen and used.

Following the AIA efforts of defining things based on the 100, 200, 300 etc. classifications, I have the following Levels and categories defined. Click the image below to see the list.

LOD_Categories

The list goes from 100 to 600 in classifications.  Each one move to a higher level of detail required.  I have included definitions and coordination lists also.

The next post will define when to put example Architectural components into the model at what phase of the project.

The Fear of Over-Modeling

Managers who oversee BIM models have a constant fear that the designers will include too much.  That they will over-model and waste time and make the model grow too large.  Fearing that someone might put too much detail into a model, some constrain the users, leaving too much out.  Others have no fear of over-modeling and allow people to plow forward spending extended hours including details that never provide much ROI for the effort.

Many have written about this issue, trying to explain the level of detail needed in a BIM model.  As I review and read these I come away with the impression that the bottom line seems to be…  add just enough to communicate the design and get it built.  This has been the standard of care in Architecture and Engineering from the distant past.  Don’t put in too much and don’t put in too little.  Many have written to tell you just that, but they do not tell you what “exactly” should be included and what should be left out.  They have some general suggestions but nothing absolute.

Isn’t there a one stop list that everyone can use?  Maybe not… Since each firm will define what is needed and try hard to get people to follow the guidelines, I can see why there is no “one size fits all”.  What your firm needs is to develop is a document that defines what goes into the model, when it is added and who adds it.  Each firm has to learn on its own, but they do not have to continually relearn and stumble over the process on each project.

Even if a list is provided, you would have to look at it from your unique perspective and project stakeholder mix.  So rather than try to give you a long list that would blindly be used and generate frustration (maybe that is why no one provides a list), I think that the process should be to create your own list.  But how should that be done?

The first thing you need to do it determine your perspective.  What used to be called a Level of Detail Specification is now moving toward a Level of Development Specification.  You need to determine which you are going to be focused on.  There is a difference.  Level of Detail usually is focused on what goes INTO the model.  Level of Development usually focuses on what you GET OUT of the model.  Subtle difference, but it can change your document.  I will not fight over the wording, but the first defines what your designers put into the model from the object level.  “Do I add exhaust hoods now?  Do I detail out the wall cabinets and light fixtures now? Do I grab that component model off the web and slam it into my design as is?” And the second defines what you will get out of the model and that determines what goes in.  “Will I render that area?  Will the Structural Engineer need that information?”

My perspective is that it is a little of both.  Sometimes you have to think about individual objects and what is needed and other times you have to keep in mind the goal of what does this model need to produce.  Balancing the two will give you some flexibility so as to not lock down a restrictive environment.

In 2008 the AIA developed “Document E202™ – 2008 Building Information Modeling Protocol Exhibit” a PDF example document that is helpful to use as a guideline. Take a look at it and we will continue to discuss this in a future post.

 

Book Review – Revit Architecture 2014 Essentials

I posted a book review on my sister site – CADDManager.com.

Book Review – Autodesk Revit Architecture 2014 Essentials

Take a look at it over there.  I posted this Revit book review there since all of my book reviews are on that site.

Mark

Revit 2014 System Requirements

Here are the system requirements for 2014 family of Revit products.  Most people are ramping up the RAM to the max they can afford/install.  It will pay off if you can do that.  So you should ramp up to the Performance level when you can with high spin rate Hard Drive for point cloud (if needed) and more RAM.

Revit 2014 Product System Requirements

For Revit 2014, Revit Architecture 2014, Revit MEP 2014 and  Revit Structure 2014

Minimum entry-level configuration

  • Windows® 7 32-bit Enterprise, Ultimate, Professional, or Home Premium edition operating system
  • Single- or multi-core Intel® Pentium®, Intel® Xeon®, or i-Series processor or AMD equivalent with SSE2 technology (highest affordable CPU speed rating recommended)
  • Multiple cores for many tasks, up to 16 cores for near-photorealistic rendering operations
  • 4 GB RAM (Usually sufficient for a typical editing session for a single model up to approximately 100 MB on disk. This estimate is based on internal testing and customer reports. Individual models will vary in their use of computer resources and performance characteristics.)
    • Models created in previous versions of Revit products may require more available memory for the one-time upgrade process
  • 5 GB free disk space
  • 1,280 x 1,024 monitor with true color
  • Display adapter capable of 24-bit color for basic graphics, 256 MB DirectX® 11-capable graphics card with Shader Model 3 as recommended by Autodesk
  • Microsoft® Internet Explorer® 7 (or later)
  • MS-Mouse or 3Dconnexion®-compliant device
  • Download or installation from DVD9 or USB key
  • Internet connectivity for license registration and prerequisite component download

Value: Balanced performance

  • Windows® 8 64-bit Enterprise or Professional edition, or Windows 7 64-bit Enterprise, Ultimate, Professional, or Home Premium edition operating system
  • Multicore Xeon or i-Series processor or AMD equivalent with SSE2 technology (highest affordable CPU speed rating recommended)
  • Multiple cores for many tasks, up to 16 cores for near-photorealistic rendering operations
  • 8 GB RAM (Usually sufficient for a typical editing session for a single model up to approximately 300 MB on disk. This estimate is based on internal testing and customer reports. Individual models will vary in their use of computer resources and performance characteristics.)
  • Models created in previous versions of Revit software products may require more available memory for the one-time upgrade process
  • 5 GB free disk space
  • 1,680 x 1,050 monitor with true color
  • DirectX 11 capable graphics card with Shader Model 3 as recommended by Autodesk
  • Internet Explorer 7 (or later)
  • MS-Mouse or 3Dconnexion-compliant device
  • Download or installation from DVD9 or USB key
  • Internet connectivity for license registration and prerequisite component download

Performance: Large, complex models

  • Windows 8 64-bit Enterprise or Professional edition, or Windows 7 64-bit Enterprise, Ultimate, Professional, or Home Premium edition
  • Multicore Xeon or i-Series processor or AMD equivalent with SSE2 technology (highest affordable CPU speed rating recommended)
  • Multiple cores for many tasks, up to 16 cores for near-photorealistic rendering operations
  • 16 GB RAM (Usually sufficient for a typical editing session for a single model up to approximately 700 MB on disk. This estimate is based on internal testing and customer reports. Individual models will vary in their use of computer resources and performance characteristics.)
    • Models created in previous versions of Revit software products may require more available memory for the one-time upgrade process
  • 5 GB free disk space; 10,000+ RPM for Point Cloud interactions
  • 1,920 x 1,200 monitor with true color
  • DirectX 10 capable graphics card with Shader Model 3 as recommended by Autodesk
  • Internet Explorer 7 (or later)
  • MS-Mouse or 3Dconnexion-compliant device
  • Download or installation from DVD9 or USB key
  • Internet connectivity for license registration and prerequisite component download
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