Video Tip - How to Trace 2D Drawings to Create Your Model

[Eric Bobrow]

I have prepared a new video tip on a topic that should be of interest to many ArchiCAD users. In this demonstration, I show how to bring in 2D drawings (in this case, DWG files) as a tracing reference to make it easy and fast to create an accurate 3D model.

The video may be viewed here:
http://www.archicadtemplate.com/?page_id=864

At this point, it is about 90 minutes long, and shows every step along the way. I plan to condense it down to focus on the principles and show only the most important steps. Note that for this long version there is a timeline control strip, so you can jump to any point you wish, or replay sections at will.

Here is an outline of the process:

• * Create a new project
  * Import the DWG files into separate Worksheets and coordinate their origin points
  * Set up the Story Levels to correspond to the project heights
  * Use Virtual Trace to reference the ground floor DWG as a background while working on the ground floor plan
  * Move the original MasterTemplate base slabs, elevation and section markers, and gridlines to the vicinity of the traced DWG
  * Set up the wall tool for the proper thickness and height, then trace the outline of the building
  * Repeat for the upper story
  * Place windows in the walls using the plan DWGs as references for location and width
  * Open each of the Elevation viewpoints and correspond the DWG Worksheets for trace reference
  * Adjust window heights, types and glazing patterns to match the original drawings
  * Repeat for the doors, first on plan, then in elevation
  * Draw the first roof piece on plan by tracing over the roof outline from the original drawing
  * Coordinate the height and thickness of the roof in each elevation
  * Use these adjusted settings to create the rest of the roof system on the lower level, then repeat the process for the upper roofs
  * Trim walls to the roofs to clean up the model
  * Adjust some of the windows and doors to have arched tops with bricks above
  * Review the 3D model, elevations and plans, which now correspond beautifully to the original drawings

All of this was done in real time, in 90 minutes!

To be frank, the first time I did this it took between 3 and 4 hours, because I had to become familiar with the project and how the DWGs were organized. The second time it took about 2 to 2 1/2 hours, and then I started over and recorded the process the third time in 90 minutes from start to finish.

In the near future, I will condense this video into a shorter presentation, perhaps 10 - 20 minutes long, and create an article that explains the process.

I look forward to your comments and feedback.

[Anonymous]

Thanks for posting the video. It's an excellent introduction to the process and very easy to understand for the beginner. I watched it yesterday in 20 minute segments, and I thought of a few general points and questions I might ask.

1 - Why did you set the floor level so high? Would using reference levels be better, and keep the lower floor at 0.00, or are there disadvantages you have found?

2 - Rather than using the elevations to help construct and position the walls and roof, I would have thought using the sections would be far more accurate. The elevations are just a by-product of the arrangement of the construction elements inside the building. You can only see this in the 2d building sections.

3 - I notice you position the roof pivot lines actually on the very edge of the roofs. I find it inconvenient in that position as it gets in the way of editing the shape of the roof. You often get a pivot line node in the same place as an edge node and can't easily choose between the two. Also, would it not be more accurate to use the walls as actually modelled below rather than the wall outlines on the 2d roof plan to position the roof, because as you demonstrated, the 2d drawings are not always accurate.

4 - It might be helpful to the new user to demonstrate using keyboard shortcuts for mirroring and copying elements after a while. You only have to show the right-click menu method a couple of time, as long as you clearly state what keys you are pressing to invoke the shortcut e.g. Ctrl+M Ctrl = mirror a copy.

[Steve Jepson]

"Eric Bobrow" wrote:
Steve -…
“Regarding your comments about using the magic wand to automatically trace the exterior - this sometimes works very well, but I often find that it breaks up walls on either side of windows or doors, or continues walls from exterior to interior, or makes other "mistakes" because of the way it interprets the sequence of lines. It may work in some contexts, but not others, and often requires extensive cleanup. Drawing the outline manually allows me to judge when the wall continues and when it doesn't, and requires less cleanup.”

Sometimes you can trace the walls faster than you can find an appropriate set of lines from the foundation plan or somewhere, add or edit some lines, consolidate, paste into a fresh plan, and then use the magic wand to convert it into 3d. It depends on the project and how the original .dwg was made.
However, the floor plan is not a very good place to get the lines you would convert with the magic wand into exterior walls, and the floor plan is not a very good place to start modeling when you already have a complete set of 2d working drawings.

If you let the actual construction process be your guide for how to create the model it will automatically generate a great many efficiencies in the process of conversion. Problems such as you have listed above with using the magic wand on a broken up set of lines is not because the technique is inefficient, it is because you are trying to use the wrong set of lines at the wrong time.

Also, if you follow the “model it as you would construct it” process, you will be able to generate from your own precision model, more and more of what you need as you go along. You will be using your model as the trace reference more than the .dwg.

The fundamental process of converting a 2d .dwg plan to an ArchiCAD BIM should not be based on a strategy of re-drawing everything.. We have tools for converting things faster and better (sometimes) than they can be re-drawn.

Use the Consolidation Tools, Quick Layers, Gravity Tool, Profiler, Magic Wand, Align, Favorites, etc… ArchiCAD has a great set of tools for converting a 2d .dwg plan into a completely functional ArchiCAD BIM. I did not see even one of these very powerful tools used in the video. This is because the process being used has no need for them. This makes my point very well.

Redrawing the walls on top of Trace Reference is only one aspect of how to make a plan to model conversion. In the next video, show off some of ArchiCAD’s more powerful and time saving tools.

Also, reconsider the final objective of the video. In the end, this video demonstrates how to re-draw over things to make a useless model of the shell.

“There is a LOT more to a good template than you can achieve by copying and pasting.”

Like what? And how much time does it actually save over tweaking or importing some configuration on the fly? Name one thing and I will be impressed.

[Eric Bobrow]

Peter -

Thanks for your positive comments, and your suggestions and questions.

1 - I set the floor level to the actual elevations as noted in the original drawings. This is not the only way to work, but it's conceptually simpler for this situation. It allows comparative reference to the original DWGs, and later on, the grading plan or site plan may easily show these heights using the point elevation dimension tool. Alternate approaches include setting the project 0 point to the top of the ground floor slab, or a convenient grade point outside, or even to a nominal height (for example 1300', since the building started at about 1385'). With ArchiCAD's built-in ability to have several reference levels, all of these are possible and can work well. I just chose the one that seemed simplest to understand for this situation, and demonstrated one of the "tricks" that is required to adjust story heights by large values (i.e. using the height to next to push up the story above, before setting the height of the ground floor).

2 - You are correct, sections are a more accurate reference for construction purposes. I chose to use Elevations since I was primarily concerned (in this video) with building a shell and matching the windows and doors and rooflines to the drawings. The basic principle I demonstrated of using the DWG as a background to compare against the model as it is being created and edited can be used with sections and even detail drawings very easily.

3 - Again, you are correct, the roof pivot lines are more properly placed on a wall edge, perhaps at the inside or outside face of framing, so that the height set for the roof matches the plate line. I wasn't sure which edge line to use, since the walls had some bumps in and out, so I took the simplest path for demonstration purposes. Note that you can always move the roof pivot lines later and check the heights to maintain the position of the roof.

4 - Keyboard shortcuts are wonderful, and I use them all the time. During demonstrations, however, I often like to make it explicit what command I am using by using a menu or button. Since I was doing the same things multiple times, you are very right, I could have introduced the keyboard shortcuts for these operations.

Thanks again for your comments, questions and suggestions.

[Eric Bobrow]

Steve -

In this video I attempted to show one approach that could be used as part of the workflow in certain situations. I never said this was the ultimate method that all users should follow.

You are very sophisticated, and understand that in many cases there are multiple sources of information that can be used to create a model. The foundation plan may be a simpler structure to autotrace. Of course, when autotrace doesn't work to your satisfaction, sometimes it is possible or necessary to consolidate lines and edit them to get a good outline for the autotrace. I believe this is harder for less experienced users to understand, so my video focused on a very approachable method that anyone could use. Please go ahead and continue to work the way you prefer; I'm sure it is a better solution for you.

You mentioned "using your model as the trace reference more than the .dwg". I pointed out that some of the windows were out of alignment in the elevation view compared to the original DWG. This is an important point - the model showed a discrepancy between the original drawings because of lack of coordination. I also saw (but did not point out) that the roof lines didn't match from one elevation to the other - one showed a hip, the other a gable.

This is why the model is not "useless" when one redraws over the DWG - it is a great way to coordinate the information! Variations of the techniques I outlined are used by many general contractors now, with ArchiCAD and Vico software as well as other options, in order to ensure constructability by checking the coordination of all drawings (architectural as well as structural and mechanical, etc.).

Yes, I agree that it is best to start a design at the beginning in ArchiCAD, or as early as possible, and that there are many advanced and powerful features that this video did not highlight. I simply wanted to show a particular approach that can be useful for many common situations:

• * as-built drawings for buildings that are being altered
  * modeling for rendering and presentation
  * creating a model for coordination
  * this can also be helpful for new users to learn ArchiCAD - creating a model of a building they've already designed and drawn in 2D.

Please check out a couple of my Tips and Tricks articles that cover some of the wonderful ArchiCAD features that you mentioned:
Quick Layers Palette (ArchiCAD Insights Tutorial) | Cadalyst - http://www.cadalyst.com/aec/quick-layers-palette-archicad-insights-tutorial-3753
ArchiCAD Favorites and Visual Legends - AECbytes - http://www.aecbytes.com/tipsandtricks/2006/issue13-archicad.html

You also may appreciate the video tip that I created in November 2009, that shows some of the shortcuts for creating a roof system with profiled rafter tails. It uses a lot of ArchiCAD's more powerful tools such as the Profile Manager, Solid Element Operations, wireframe use of layers in 3d, autotrace with the magic wand, and the roof framing wizard:
Creating Rafter Tails - on the ArchiCAD MasterTemplate website - http://www.archicadtemplate.com/?page_id=554

For more information on the power of templates, and tips for setting up your own templates, please read my article in AECbytes:
ArchiCAD Office Standards and Templates - http://www.aecbytes.com/tipsandtricks/2008/issue30-archicad.html

Thanks for sharing your perspective, and prompting me to explain further some of the reasons that I approached this video in the way that I did. I appreciate your input.

[Eric Bobrow]

Steve -

One more thing...

In response to your challenge to "Name one thing" that saves time over importing a configuration on the fly, here are several ways a robust template saves time compared to the standard Graphisoft template:

• * Views in the View Map can be setup in the template for almost all standard Drawings (whatever is typically needed for a project) and many of them can be pre-placed on Layout sheets, in many cases needing only minor adjustments once the model is created and annotated
  * Title Pages and other frequently used Layouts such as General Notes can be preset in the Layout Book with contents that are linked to the model, to the Project Info, and to external PDF or other files
  * Extensive sets of Favorites can be maintained and developed for the template, either using the Favorites palette or (my preferred method) as Visual Favorites in the form of an Interactive Legend for eye-dropping
  * Attributes can be developed over time to create a library of materials, fills, composites, linetypes and complex profiles that make it easy to have quick access to most everything you need for a project, minimizing how much needs to be created each time you start
  * Typical room configurations can be saved as part of a template to make it fast and easy to fit out a building - with the option to edit as needed for the design context
  * The basic principle is to reuse element definitions, project structure and relationships as much as possible, so that when you start a project you already have a lot of the setup and clerical work done.

You can accomplish much of this without using a template, of course. Simply take a really well-developed project, save a copy under a new name, and delete the building geometry and annotations while leaving the structure (including section and elevation markers and the Layout Book with placed Drawings) intact. However, not all projects are suitable for reuse in this way, and most people don't know how to set things up so they work over and over again in the most efficient manner.

We have spent hundreds of hours developing the ArchiCAD MasterTemplate to embed the Best Practices as we understand them. It is certainly not the only way to go - for no general purpose template can possibly anticipate everyone's needs and architectural styles and requirements. However, we have hundreds of enthusiastic users who say that MasterTemplate has saved them lots of time, and helped them to use ArchiCAD much more effectively. To see more info on MasterTemplate, please visit our website http://www.archicadtemplate.com.

Again, I'd like to thank you for your comments and your passion! What you wrote made me think, and led me to take the time to explain more of the concepts and thoughts behind all of my work.