Friday, July 10, 2009

Revit Render Trick

Structural renders are getting used more often and the mental ray engine leaves a grey line at the horizon, here's a little trick to bypass the grey horizon line in renders, it's not great but it's quick:

  1. Render an image and save to .tif or .png - This will create an alpha channel transparency with no sky, and no horizon.
  2. Change the the target of the camera to be 100m or so in the air so that nothing but sky is seen, re-render and save the sky image as a .jpg - This renders really fast as there's no geometry
  3. In photoshop (or image software of your choice) add the sky in behind the image.

4x6, FRONT VIEW .png image (with alpha channel)

sky .jpg image

4x6,-FRONT-VIEW composite (.jpg was rotated 180deg.)

The final image looks better once more scene assets are added and you don't need to place an expensive (in render time) tree line along the back of the image.

2010 Updates Available

AUTODESK® REVIT® STRUCTURE 2010 Update Enhancement List

Revit Structure 2010

http://usa.autodesk.com/adsk/servlet/item?siteID=123112&id=12856705

Revit MEP 2010

http://usa.autodesk.com/adsk/servlet/item?siteID=123112&id=12899931

Wednesday, April 29, 2009

FBX file size issues

It's been a while since I've posted anything but I've been quite busy and these days that's a good problem to have!

I saw this topic at the Autodesk Revit Architecture Services & Support RSS feed I subscribe to and I thought it would be good to point it out since renders are becoming more & more important in all the disciplines:

Issue

You want to know why the size of an FBX file exported from Revit® is larger than the original Revit RVT file.

Solution

The original Revit file does not contain the same data as the FBX file. Revit scene file information is based on Revit-specific construction information obtained from the Revit software and is more view-specific in nature.

When this data is exported as an FBX file, it is converted to complex FBX scene information based on geometric data, such as vertex coordinates, UVs, and material data, which is embedded in the FBX file...

read the full atricle here

Tuesday, March 17, 2009

Automatic Point Alignment

A helpful little tool that seems a little bit hidden, at least I've not seen or heard of it before.  When adding walls with the draw tool & the location line set to centre of wall I noticed that revit was finding the centre of pairs of lines in my cad file underlay.

auto alignment

fig.1, my cad file underlay

auto alignment (1) auto alignment (2) auto alignment (3)

fig.2, 3 & 4, revit assuming parallel lines are really walls

 auto alignment (4)

fig.5, nice that's the point I wanted :)

Monday, March 16, 2009

Revit 2010 UI Update (Screen Real Estate)

I can't remember the last time I was excited to get my hands on an update to a software package so much as I am for revit's 2010 update.  I am terrified of the ribbon mainly due to experiences I've had with it in autocad slowing to a snails pace but autodesk has assured us that this will not happen in revit.

What I'm most happy with is this quote from Inside the Factory "Another enhancement concerned the project browser. We observed many customers running with the browser undocked on a second monitor, despite having to re-set it every session. Revit 2010 now remembers the project browser state and location between sessions...Concerning dual monitors,  I can say that multi-monitor support is one of our most highly requested UI features. We are actively researching this topic and we would like to hear more about your frustrations, experiences and suggestions concerning multiple monitors."

Check out the full inside the factory post on Screen Real Estate and be sure to let them hear from you.

Tuesday, March 3, 2009

Project Collaboration

I don't know how many saw the latest issue of AUGIWorld but it included a great article on collaboration by Jamie Richardson.  This article should be required reading for anyone (not just structural) using revit.  I have, with Jamie's permission copied the article here.

 

Redefine your Collaboration Workflow

by: Jamie Richardson

 image

By now I am guessing that most of you are already using Revit® Structure to produce your design documentation, and, if you aren’t using it, more than likely you are at least considering it. If you aren’t looking at it, what are you waiting for? The use of Revit for any discipline definitely changes the workflow for you. If the workflow is not changing, then you were doing it way different than the way I was doing it! How different this workflow becomes depends a little bit on how much you are willing to change how you have been doing things in the past with other 2D CAD applications. Let’s take a second and reminisce about what I now call the “Old School” 2D days of CAD.

Old school CAD

As structural professionals, we would always receive what everybody said was this perfectly good CAD file from the architect. This file contained everything we needed to produce our structural documentation, we were told. The thinking went something like this: “They already have the grids laid out. Let’s just trace over them, or better yet, let’s just copy/paste them into our file, or much better yet, let’s just save their file as a new file, delete information that is not needed, and make it our structural file.” In return, the CAD manager would say, “Absolutely Not! We are going to verify every single line, dimension, text, and draw our own information in our file.” Why was this done? Because over time we began to lose faith in the accuracy of the drawings we were receiving. Structurally, we wanted precision set to 1/256" and “they” wanted it set to 1/16" or sometimes even 1/8". Other programs were used to produce napkin sketches of the building during schematic design and those sketches were being pulled into CAD. Sometimes the sketches were turned into nice numbers that were easy to work with and other times it looked like they were just left as sketches. The bottom line is we could not trust the CAD files to enable us to produce an accurate set of drawings that would allow other parties, such as fabricators, to use downstream. Using Revit on a project changes all of that; at least it needs to in order for the whole process to work.

The workflow needs to change

What needs to change? First, everybody needs to start producing accurate models that we all can trust. This means that those working on the project are going to have to step up their game a bit and go that extra mile to make things correct. Without this accuracy in the Revit models you are sharing, you will have little chance of relying on someone else’s model. Second, we need to start communicating again. No more of the architect moving an elevator shaft over 6" so he or she can maintain a certain corridor width and not tell structural it was done. Drawings get issued, it gets built from the structural drawings, and the elevator shaft is constructed in the wrong location. There can be no more of the engineer changing a beam depth size and not telling mechanical. The field guy is installing some duct work and finds out that his duct work does not clear the bottom of the beam. Dropping it would lower the ceiling height. Who wins? I could go on and on with scenarios from all sides of the design team, but right now I would like to talk about how Revit can eliminate this. Using Revit to model your projects and to produce construction documents is a chance to regroup with everyone and change the way you have been doing things in the past. I know that some of you who have been doing this correctly, but I also know that there are others using the undesirable methods described above. So let’s discuss the workflow that can get you started in a new direction.

Using a dependent collaboration workflow

What do I mean by dependent collaboration? Well, this means that each discipline models only the elements for which it is responsible. Architectural should not be modeling footings, foundation walls, columns, framing, and structural slabs. Structural shouldn’t be modeling exterior finishes and door/windows to show how they relate to a lintel or a foundation wall. And I have to believe that Mechanical does not want to model any of that, preferring to model its own discipline specific elements. Can all of this happen 100 percent of the time for every project? No. You will face challenges that might discourage you from thinking that any of this makes sense, but hopefully as you are reading this, you are thinking about what part of this workflow might allow you to take advantage of the same benefits we see when we work on projects in this manner. Some project schedules might not allow for this workflow and certain structural systems may accommodate this more easily than others. There will always be scenarios that will prevent some of these efforts from being carried out to the fullest degree. But over time, I see this slowly decreasing as the workflow is further defined. At my company, this method of collaboration is what we try to use on the majority of our projects. The goal for all team members is to avoid modeling anything twice. If this can be done, then your model has to be coordinated or your drawings will not be correct. Figure 1 shows a structural section that clearly is not coordinated.

image figure 1

image figure 2

The red indicates that the architectural model is linked into the structural file. This information is not modeled by structural; structural can’t change it because it is linked into our model. We could lower the trench footing down, but whose model is right? Well, I’m going to say that structural’s model is right because structural is always right! Of course, the architects will say they are always right. Seriously, we could both change our models to be correct, but the next time we exchange our models the section would be wrong again. In the past, we would each change our drawings and when the drawings were issued we would not be coordinated.

With Revit, you can be dependent on each other’s work, so as long as you are communicating about whose model is correct and you are using the most up-to date models prior to printing, you will be coordinated. At least if your section is wrong, it will be wrong in the same way throughout everyone’s documents.

What does the structural engineer use from the architectural model?

  • Doors
  • Windows
  • Walls
  • Curtain Panels
  • Curtain Systems
  • Curtain Wall Mullions
  • Architectural Columns
  • Stairs and Railings

What does the architect use from the structural model?

  • Footings (wall, isolated, slab)
  • Foundation Walls
  • Piers
  • Columns/Post/Hangers
  • Framing
  • Slab on Grades
  • Structural Slabs
  • Roof Deck

Now don’t get the idea that Revit is going to do all of this for you. It will, for the most part, after you determine your settings, but first you need to get yourself familiar with working with the Visibility/Graphic Override dialog box and the RVT Link Display settings shown below. Getting deep into this is another topic for discussion. So for now, if you are unfamiliar with it, check it out.

image figure 3

image figure 4

image figure 5

Also take note that getting started with all of this is going to take a bit more time than you are accustomed to, mostly because it is new method of working and thinking and you need to get past the learning curve. What I see is the time you may have spent on the phone after your documents were issued is now shifted to more time on the phone before you issue. The kick is that your time on the phone is going to be much more enjoyable and beneficial for everyone because you are fixing problems

before they are costing everybody more money. If you are just starting out, it will take more time because everyone is learning the new workflow as well as trying to understand and learn what everyone expects to happen on the project. So with that said, the most important thing for you to take from all of this is to communicate before a project is even started. Get everybody’s expectations out on the table and come up with a plan to achieve your goals.

Communicate, communicate, and communicate some more

During this communication process you need to be communicating internally to your own people, externally to other team members, and continue to communicate on a daily basis throughout the duration of the project. Currently, I find that users of all levels from all disciplines are still learning the software as well as the new work flows involved, so the level of communication required to pull this off is key. The biggest thing is to get everybody on the same page prior to starting a project. Decide what is expected and discuss the best way to work within those expectations. To do this, we push to have a Revit kickoff meeting prior to any new project. This means that the minute someone catches wind of a project starting up, someone needs to be picking up the phone to get a meeting scheduled. In this meeting we bring with us an agenda that walks the team through everything that should be discussed prior to starting the project.

What things should you talk about in a Revit kickoff meeting?

  • Identify team members and their roles
  • Set the expectations and goals for the project
  • Identify the workflow process each team will use
  • Determine who will be modeling what
  • Review how each team will be using Revit
  • Discuss limitations each team might have with the software
  • Discuss how models will be transferred and how often
  • Decide when Revit will be used (some might still use 2D CAD for SD and DD)
  • Define the deliverables (Revit model, DWF, DWG, hardcopy, model presentation)

You might also consider creating a separate document that is more specific to your company regarding your own list of expectations in terms of what will be in your model as well as what will be in someone else’s model. Be prepared to manage expectations that are not met. You may be dealing with someone who is new to Revit or a client with whom you haven’t worked before. Either way you need to be ready to deal with the consequences of a changed workflow and you must relay that workflow back to your own team. At least with the BIM/Revit kickoff meeting, you are dealing with these problems up front rather than waiting until the day of a deadline or after an issue arises. The use of Revit gives you the perfect excuse to embrace change and redefine your collaboration workflow. Revisit the accuracy of your drawings, duplication of effort, and how you communicate. Over time I think you will find that it was the right thing to do. So what are you waiting for? Go ahead, call your client or your consultant. Set up a meeting to see how you can use Revit to collaborate on your projects and maybe even change things up a bit with regard to how you work on a project. Who knows, with your next project, you might just be able to leave work on time!

image Jamie D. Richardson is an Associate and CAD\BIM Manager at Ericksen Roed & Associates, a Structural Engineering firm based in Saint Paul, Minnesota, USA. Throughout his 14 years of experience with Autodesk products, Jamie has been instrumental in the rollout of several versions of AutoCAD as well as the implementation of Revit Structure. He has been an avid speaker on Revit Structure at Autodesk University and recently co-authored the book Mastering Revit Structure 2009. He can be reached at jrichardson@ericksenroed.com.

Tuesday, February 3, 2009

Custom Glazing

Ok so this is revit architecture, I use it too :)

On a current project I need to render a few images to give the client some glazing options.  I contacted a supplier and they were just in the early stages of creating revit families of their glass colours.  (Nice to see new families being created by suppliers!)  They were having a problem getting the colour to come through on their renders.  I started working with them to create custom glazing and I made an error in assumption at the start: I thought to use the generic material as my base point as it should give me access to all the material settings however there proved to be too much control and I found it difficult to get a handle on what all the variables controlled.  I would suggest only going this route if you have a fairly good level of experience with 3D graphics and render options.

The faster way to go, and this is the trick, is to pick a render material that is close to the material you want to create.  From the supplier I got an RGB colour value of 139/152/136, a reflectivity of 30% & a transparency of 53%.  As you can see the bas material starting point is very important.

Curtain Wall Glazing

dark green ref ScreenShot001, 2 panes

light blue rippled light blue rippled-result

mirror-set mirror

Etched Glass Settings

etched settings etched settings (1) Untitled-1

I didn't spend any time on the orientation or tiling of the flower image and as a result it was rotated 90deg. & tiled a few times both horizontally & vertically.

A quick note on the differences between transparency & translucency.  A transparent physical material shows objects behind it as unobscured and doesn't reflect light off its surface. Clear glass is a nearly transparent material. Although glass allows most light to pass through unobscured, in reality it also reflects some light. A perfectly transparent material is completely invisible.

A translucent physical material shows objects behind it, but those objects are obscured by the translucent material. In addition, a translucent material reflects some of the light that hits it, making the material visible. Physical examples of translucent materials include sheer cloth, thin plastic, and smoked glass.

Transparent and translucent are often used synonymously. Materials that are neither transparent nor translucent are opaque.