working with revit & navisworks

Collaborating with Navisworks can be a great way to communicate with all the project partners, it can also create some headaches.  As collaboration gets more and more detailed each discipline needs to better understand the other disciplines and their working requirements.  (This makes any employee who understands more than their isolated discipline a much more valuable  asset!)  One workflow is to have both Revit and Navisworks open and to co-ordinate geometry by exporting NWC files from Revit and updating the Navisworks model.  In order to be effective and productive this has to be done as efficiently as possible, I am currently attempting this workflow only to be ground to a halt for 6-8 minutes every time I refresh my Navisworks file.  Although to be honest it is giving me both the impetus and the time to write this entry Smile  So let’s go over a quick how-to for using Revit and Navisworks to help speed the process up.

What to Export

Always export only your own information!  I can not emphasise this enough – everyone else is going to do the same so if you are the electrical there is no need for you to include the architectural model.  As an example, the electrical model would look like this

    Screen Shot 04-10-15 at 02.48 PM

So make an isolated 3D view (good practice is to name it “Navis” more on this another time) and go through the Visibility Graphics settings and turn off everything is not directly your own responsibility.  There is a quick category caveat – family elements set to generic or speciality equipment may be from many different disciplines, think about editing them to make your families your own discipline or use VG filters to isolate your own.

HOW to Export

During the export to NWC there is a place to choose the Navisworks Settings…

Screen Shot 04-10-15 at 03.08 PM

 

My settings look like this

Screen Shot 04-10-15 at 03.11 PM

convert construction parts: unless you are the GC you likely don’t need to use this

convert element ID’s: this is the unique identifier for each element it could be left on

convert element parameters: Basic Revit properties will be included in the Navisworks file regardless of this setting.  Checking this box will do 2 things during the export process:
1.  Additional properties will be included with the resulting Navisworks file.  These include properties for Navisworks related to the element properties, object orientation, material information, associated level, worksharing information, family specifications, cuttability and Revit object category.
2.  Depending on the size and number of objects in your project, the export time can dramatically increase as additional properties will be translated.  For example a 100 MB file with this unchecked may take a few minutes.  Check the box and the export time may jump to 20 minutes.  This is something to keep in mind if you don’t need the additional information in Navisworks. – PLEASE PLEASE UN-CHECK THIS

CheckedConvertProperties

Unchecked

NoProperties

convert element properties : consider not including these (see above)

convert linked files: please don’t include

convert room as attribute: unless you are the architect this is not required

 convert URLs: will include any URL’s associated with families

coordinates: this depends on the project specific settings

divide file into levels: helpful as it divides the selection browser to include levels but it’s not required if you don’t need it

 export: current view: YES – this is why we made the “Navis” view – there is another reason to name it “Navis” but that is for another day

export room geometry: do you really need the room to be a transparent object in Navisworks getting in the way of EVERY attempt to select something? consider not checking this.

try to find missing materials: if they are missing here they are gonna be missing everywhere, who cares?  if you couldn’t be bothered to find them and set up your Revit with them then they are obviously not important enough to be brought into Navisworks.  besides we can add materials in NW and then render but again that’s for another day.

Calculating BIM’s RoI

I saw this article from Cadalyst, take a read if your still not convinced that BIM is the right way to go…

 

With the advent of BIM (building information modeling), the building industry is coming to appreciate that technology can radically transform the building design and construction process. But before committing the funds to purchase that technology, the bean counters in an organization will probably insist on ROI (return on investment) analysis.

 

At that point, the folks tasked with producing the numbers usually grimace in pain and start twitching. But there’s an upside to ROI analysis. Although primarily used to justify a purchase, calculating ROI for a technology investment forces those involved to reach an agreement about why they are spending the money and what results they expect.

 

This month’s article delves into ROI for BIM solutions — which variables to consider, a sample formula and typical numbers, and a heads-up as to what the ROI metric overlooks.

 

ROI 101
ROI analysis is one of many ways to evaluate a proposed investment. It compares the gains anticipated from an investment against the cost of the investment.

 

Earnings/Cost = ROI

 

The ROI approach can evaluate many types of corporate investments, from R&D projects to training programs to fixed-asset purchases. The more complicated the investment, the more complicated the formula becomes. Just think about calculating the total cost of a departmental Microsoft Office upgrade versus calculating the total cost for a worldwide ERP implementation! And as the investments get larger, the creativity required to calculate the ROI becomes more significant, eventually entering the realm of black art.

 

ROI for BIM Investment
Mercifully, calculating the ROI for a design system can be relatively easy. The only hitch is that you need to consider the changes in user productivity during ramp-up. The diagram below (figure 1) illustrates what happens after you put a new system into place. There’s an immediate dip in productivity as users get up to speed on the new system. With time, productivity climbs back to where it was with the original system and levels off at a higher point as the new technology takes hold.

 

figure
Figure 1. Visualize what happens when you put a new system into place.

 

A standard formula for calculating the first-year ROI is in figure 2. It uses just a few key variables related to system cost, training, and the overall productivity cost savings of a system. The next figure shows the formula variables (figure 3).

figure
Figure 2. A standard formula for calculating first-year ROI.

 

figure
Figure 3. The ROI formula variables.

 

The numerator represents the earnings portion of the equation, which comes from an increase in human productivity. The increase in average monthly productivity is represented in the left bracket (B – (B / 1 + E). The right bracket (12 – C) is the number of months in a year minus months in training (C). If the user needs three months to become as productive on the new system as on the old, then there are nine months left in the year to benefit from the productivity gains.

 

The denominator, which is the cost portion of the equation, includes the cost of the system (A) and the cost of the productivity lost, in terms of labor cost, as the user learns the system. This second term is the product of the monthly labor cost (B) multiplied by months in training time (C) multiplied by productivity lost in training (D) — therefore, BXCXD. Note that training time refers to the time it takes a user to reach the same level of productivity experienced on the original system — not the length of a training course.

 

Number Crunching
Now let’s plug some real numbers into this equation. The sample numbers used below are typical, but of course substitute your own estimates for an actual calculation.

 

A quick note about these numbers. Autodesk commissioned an online survey of its Revit users in December 2003. Approximately 100 users responded to the survey. I will use those results, compiled in the white paper, “Return on Investment with Autodesk Revit,” as the basis for the sample numbers below (figure 3). The white paper also includes an Excel-based ROI calculator for BIM that you can use for your own ROI calculations.

figure
Figure 4. A sample ROI calculation.

 

Using these numbers, ROI is slightly more than 60%! That’s a healthy ROI for most IT investments. But every company must decide what’s an acceptable return on their investment. Small companies might need to demonstrate how they plan to repay a bank loan. Larger companies may use ROI to compare proposed uses of their working capital.

 

Critical Variables
If you play around with the numbers, you’ll notice that the productivity gain and loss are the most sensitive variables in the equation. Slight changes in those figures produce the most dramatic changes in ROI. You can understand why productivity is so critical: It’s the long-term result of an IT investment.

 

The productivity gain figure used in our sample calculation (25%) is indicative of results reported to Autodesk and a conservative estimate. One Revit customer, Rhode Island-based Donald Powers Architects, recently measured the productivity gains the firm experienced using Revit for numerous design projects (figures 4 and 5). Principal Donald Powers reports, “With about 20 projects completed in Revit, the firm has seen productivity gains of 30% in design and documentation, and a 50% drop in requests for information during construction.” In addition, training time — the time it took the staff to become as productive on the new system as the old — was just 14 days vs. the three months used in our sample formula.

 

figure

Figure 5. Donald Powers Architects completed approximately 20 design projects using Autodesk Revit, including this innercity rehabilitation project.

 

figure


Figure 6. Donald Powers Architects found that using Revit has resulted in a 30% productivity gain — a key variable used for ROI calculations — for projects including this high-end residential development.

 

In Autodesk’s recent online survey, more than half the respondents experienced productivity gains of more than 50% using the Revit building information modeling solution, and 17% experienced productivity gains of more than 100%.

 

The least important factor in our ROI calculation turns out to be the system cost, an interesting fact to remember the next time you’re involved in a technology purchase. Doubling the system cost in the original set of numbers (from $6,000 to $12,000) reduces the ROI by only 20% (from 61% to 41%).

 

ROI Limitations
ROI is a popular metric, for sure. It boils down a complex soup of numbers into a single percentage everyone can digest. But beware: The ROI metric is more accurate for cost-saving projects than for revenue-generating projects. ROI analysis works best for IT implementations that produce tangible, easy-to-measure cost benefits, such as improved productivity.

 

When calculating ROI in terms of revenue generation, analysts often use estimates — lessening the accuracy of the results. A more extensive ROI on the adoption of BIM could include profit gains from increased billing, project quality, and increased repeat business; improved communication and client presentations; links to external analysis applications; and so on. The difficulty is in projecting the value of those gains.

 

For example, one respondent to the Revit survey stated that adopting BIM had shifted the time split between traditional design and documentation. Using Revit decreased the hours the firm spent on producing construction documents by 10%, allowing users to spend that extra time in more constructive, up-front design work. As a result, the firm was reevaluating its fee structures. This profitability boost may be complicated to calculate, but you could certainly factor it into a more complex ROI analysis.

 

Likewise, another survey respondent (a 300-person architectural firm) reported that it completed several projects using Revit with half the budgeted staff and in half the budgeted time. It would be easy to factor in the reduction in budgeted time — a direct component of productivity — but the ramifications of the excess design staff is a bit more complicated and more difficult to quantify.

 

ROI: Final Thoughts
If you’re asked to help determine the ROI for building information modeling, don’t go into a tailspin. Adopt the viewpoint that it’s a necessary evil and turn it into a useful learning experience for yourself and your organization, providing crucial insight for future projects. And once the ROI is complete and the technology is in place, don’t forget to measure your organization’s actual performance against the expectations.

 

– See more at: http://www.cadalyst.com/aec/calculating-bim039s-return-investment-2858#sthash.eBcYyxzY.dpuf

An Updated look at LoD

As BIM authors become more adept it quickly becomes apparent that a more hybrid understanding of 3D graphics is required.  This new level of modeling takes the technical drafter down the road closer toward a visualization or animator role.  Therefore a more specific description of Level of Detail/Development is required.  (Each RPF or BIM Implementation needs to have a section defining LoD as it’s specifics mean different things to different people.)

It it important to note that Level of Detail and Level of Development are different things… Level of Development outlines what a model is authorized to be used for while Level of Detail describes the model’s graphical properties and goes together with Level of Appearance Quality (LoAQ).

Level of Detail in General

LoD1: Buildings are represented by their footprint or the roof outline with a constant height value.  Inclusion of some density data or distances are possible.

LoD2: Buildings are represented by massing models.

LoD3: Buildings are represented by geometrically simplified exterior shell.  Analysis of the materials is possible leading to an estimated ‘R’ value of the wall assembly & energy conservation performance.

LoD4: Buildings are represented by geometrically exact exterior shells.

LoD5: Building interiors are included.

Geometric Level of Detail (GLoD)

GLoD1: Buildings are represented as 2D surfaces inserted into 3D space.

GLoD2: Buildings are represented as simple 3D geometry.

GLoD3: Buildings elements that are 15cm and larger are included.

GLoD4: Buildings elements that are 5cm and larger are included.

GLoD5: Buildings elements that are 1cm and larger are included.

Level of Appearance Quality (LoAQ)

LoAQ0: No minimum appearance quality is specified.

LoAQ2: Buildings are represented as “shaded with edges” and indicates true colour.  Includes shadows

LoAQ3: Building on the requirements of LoAQ2 but is expanded to include material mapping.

LoAQ4: Building on the requirements of LoAQ3 but is expanded to include full texture mapping (bump maps, transparency, luminance, reflectance…) to produce a photo real environment.

Connecting Revit to a Database for GIS

You can export model component data to an ODBC (Open Database Connectivity) database. The exported data can include project parameters that have been assigned to one or more element categories in the project. For each element category, Revit exports a database table for model types and another table for model instances.

ODBC export uses metric units only. If a project uses Imperial units, Revit converts all measurements to metric units before exporting to ODBC. When you use data from the resulting database, remember that the measurements reflect metric units. Use a database function to convert the measurements back to Imperial units if necessary.

Using ODBC, Revit creates tables for the following elements:

  • Model Objects: Types and Instances
  • Levels and Rooms: Instances only
  • Key Schedules
  • Assembly Codes: A single table containing assembly code data for the entire project

ODBC export creates specific relationships between tables in the database using primary keys and reference values. See Table Relationships Within the Database.

Revit can export to the same database multiple times. When exporting to an empty database, Revit creates new tables. When you export a project to a populated database, Revit updates table information to match the project. This allows you to customize the database and re-export data as the project changes.

Attention: Do not export different projects to the same database. Use a unique database for each project.

ODBC is a general export tool that works in conjunction with many software drivers. Revit has been tested with the following ODBC drivers:

  • Microsoft® Access
    Microsoft® Excel
    • An ODBC export to Excel creates one table per worksheet.
    • You can export to an Excel file only once. Multiple exports to Excel are not supported.
  • Microsoft® SQL Server
    • The Microsoft® Text Driver is not supported by Revit.

Revit DB Link allows you to export Revit project data to a database, where you can edit the data, import it back into the project.

There are two types of databases you can use with Revit DB Link: Microsoft Access or ODBC.

The database must already exist (for non-Microsoft Access databases) and have a DSN properly set up for connecting to it. See Accessing Revit DB Link.

The Microsoft Access or SQL Server database must allow for reading, writing, and table creation.

When Revit creates database tables during ODBC export, it adds relationships to the data tables using primary keys and reference values. In relational databases, a primary key is a unique value that identifies a record (row) in a table of the database. Reference values are columns in a table that refer to other tables.

Note: Database programs (such as Microsoft® Access) can interpret the table relationships. In spreadsheet programs like Microsoft® Excel, relationships are not supported, so Revit creates simple, unrelated tables.

The primary key in each element table is the column labeled “Id”. The following table illustrates how primary keys and reference values create relationships among tables in the database.

Column (Field) of a Door Instance Table Corresponds to…
Id

This is the unique identifier for this instance of a door.

Type Id

Id column of the door Types table

Level

Id column of the Levels table

Room

Id column of the Rooms table

Key schedule

Id column of the Key Schedules table

The primary key in the Assembly Codes table is the Assembly Code column. The Assembly Code column in type tables references the Assembly Code column in the Assembly Codes table.

Revit does not create a reference for the Host Id column because the host may be a wall, floor, roof, or other such host, so there is no unique table to reference.

The relationships between tables are established only when Revit first creates the tables; if you use Revit to re-export to an existing database, no new relationships are created.

You can install the Autodesk Revit DB Link 2014 from your subscription site.

To export to an ODBC database
  1. In Revit, open the project to export.
  2. Click Export (ODBC Database).
  3. In the Select Data Source dialog, click New to create a new Data Source Name (DSN).
  4. In the Create New Data Source dialog:
    1. Select a driver, and click Next.
      1. This driver is associated with the software program you export to (for example, Microsoft® Access, dBase, or Paradox).
    2. Enter a DSN name, or navigate to the target folder and specify a file name. Click Next.
    3. A confirmation dialog displays. If any information is incorrect, click Back and correct it.

    4. Click Finish.
  5. Create the database file.
    1. Depending on the driver selected, a dialog displays, requesting information about the database file to which you’re exporting. Use the dialog to specify the database to use or to create a new one. For example:
      1. For Microsoft® Access, click Select to select an existing database, or click Create to create a new, empty database to export data to.
      2. For Microsoft® Excel, first use Excel to create a new, empty workbook with the desired name. Then on the dialog, click Select Workbook, and navigate to the new workbook.
  6. In the Select Data Source dialog, click OK.
  7. In the ODBC Setup dialog, click OK.

Note: If the export fails with an error regarding a read-only database, click Options in the ODBC Microsoft Setup dialog. Clear the Read Only check box. Then try the export again.

Do not edit data in the database columns exported by Revit. Any changes to those columns are overwritten the next time the project is exported.

However, you can add columns to the tables created by Revit. The next time the project is exported, any data in the added columns is preserved.

You can update a Revit project with changes that were made to data in an external database, or that were directly edited during import.

  • The appropriate Revit elements reflect any changes that were made to the database.
  • The import table view allows changing of data immediately before import if desired.
  • You can use Ctrl+0 to set a cell value to empty in the table view.
  • It is not possible to delete, cut or modify an entire record (using copy and paste) if the corresponding element exists in Revit.
  • Those tables that do allow creation of new types will have a new row record available. When filled out with all the required data, the ID displays a negative value which converts to a valid element ID after the import process.
  • The Custom Parameters menu allows you to create Shared Parameters for your project. Click Add and specify the Name, Group, and Type, then select the Categories it will belong to. All selected categories that have an associated database table automatically appends the new parameter field to the table. This parameter data may then be edited in the drawing or the database and updated accordingly upon import or export.

    DANGER

    Only import from the database originally exported to for a given project, or unpredictable results may occur.

Revit DB Link Workflows

Autodesk Revit DB Link provides a way to store Revit model information in a database where it can be modified and then returned to the Revit model. With Revit DB Link, you can:

  1. Create a database from data in a Revit project.
  2. Update an existing database with Revit data that has been changed.
  3. Update a Revit project with changes made in a database.

How BIM is Changing Business

One of my colleagues passed this great article along (thanks Anthony)…

As the wind whips through the top floor of an unfinished eight-story office building a block west of the White House, Steven Denbow points to metal air ducts as an example of work that wouldn’t need to be redone.

The 29-year-old senior project engineer for Balfour Beatty Plc (BBY) ran three-dimensional simulations before construction began, finding hundreds of clashes, or design elements that interfered with each other. When the software indicated water pipes would intersect the ducts, he requested changes so workers didn’t have to rebuild parts of the $29 million project.

Armed with iPads linked to the newest plans, work orders and …read more

system requirements for autodesk products

You certainly want to make sure that your system can run the applications efficiently, one of the things your corporate principals want to guard against is the amount of lost time that can accumulate due to inadequate system performance. Things like a simple 3 second pause waiting for a screen regen multiplied by the number of times we pan around a project file can add up to a full day or week amazingly quickly. The dollar value in lost productivity in wages along soon justifies the cost of a properly specified CADD system. (Just a side note that any serious CADD system should include dual monitors.)

As I don’t know the software package you have I have included a couple links to the various system requirements that Autodesk has published. Of course it just as a wise decision that your BIM/CAD Manager be involved with IT during the purchase of new CADD systems as it is for IT to be present in our BIM project implementations.

System Requirements: Autodesk 2014 Suites

System Requirements: Autodesk Products (all years)