Dimension Driven Design (DDD) Videos

For me, DDD brings back a feeling of the old drafting skills and knowledge, it makes work so much more fun. If I had the opportunity to train people who were completely new to CAD, I would start with DDD!

Here follows a complete set of Free video tutorials running to about 3 hours in the Windows Media Video (*.wmv) format. They are aimed at all levels from casual interest to beginner to expert.

 Also a thank you note to those who provided feedback in helping make these video as comprehensive as possible, especially Sam Wilson from Bentley and Jon Summers from LA Solutions, thanks guys!

Let's get started...

 

  00 Introduction

[09:57 / 12.5MB] This first video Introduces the Parametric design concept in MicroStation, demonstrates some examples, and discusses its suitability for integration into existing work flows and standards.

 

  01 The Basics

[05:40 / 6.3MB] In this, the first video proper, the foundation components of DDD are introduced; namely Constructions and Constraints.

If watching this video series in conjunction with other DDD documentation, note that there may be some slight variations in the terminology used. For example ‘constructions' are referred as a constraint type in the MicroStation documentation, but are referred to separately here for clarity.

I had considered renaming ‘constructions' to ‘elementary constraints' for the purposes of these videos and to avoid confusion with construction class, but felt that - even though alternate naming might be more meaningful, it would probably be prohibitive to learning in the long run.

 

  02 Geometric Constraints - Part1

[07:28 / 8.15MB] This video describes the Constrain Elements toolbox, which is found under the first icon in the Geometric Constraints tool palette.
The tools found are conveniently grouped, as they create relationships for Lines and Ellipses only.

The first tool is ignored (for now), and the rest demonstrated quickly are:

  • Tangent
  • Perpendicular
  • Parallel
  • Direction

 

  03 Geometric Constraints - Part 2

[04:48 / 4.83MB] This video deals with the Point-On and Point-At geometric constraints, their implementation and usage.

I've also described an important and very useful behavior where a circle construction can be used to behave a point construction in the right circumstances.

 

  04 Geometric Constraints - Part 3

[06:18 / 6.83MB] Continuing directly from the previous video dealing with point geometric constraints and discussing:

  • Coincident
  • Equate

Finally some opinion about avoiding using the Equate Constructions command as I have found it a touch buggy. While I neglected to provide examples of this, it still useful to be aware of when trouble-shooting a problematic solution.

UPDATE: Sam Wilson has looked into this further and provided further information on how the tool works:

1. Look through all of the constraints and attachments in the model and replace all references to construction 2 with construction 1. In your test case, we want to unify two point constructions. The tool would find a reference to the second point in one of the point-at-intersection constraints.

2. Now we have the same number of constraints referring to a smaller number of constructions. That might make the model over-constrained. If so, I have to remove the redundant constraints. Here's where the trouble starts. I don't really try to understand the intent of the constraints in this tool. I just walk through the constraints and discard the ones that are contributing to the over-constrained state. As a result, I discard the point-at-intersection that relates the point and line. I admit that a better tool would replace this constraint with one that merely points the point on the line. Anyhow, that's the way the tool works. It should only cause trouble insofar as it removes too many constraints. You might have to go back an add a few.

So the issue that I was running into was that too many Constraints were being removed, but MicroStation was leaving me in the dark about what it had done. With the result that I would continue developing my solution only to discover problems at a later stage, thus making it very difficult to track down the source of the problem.

My attitude towards the Equate Constructions tool is now: Still avoid using it, since it can still only be seen as a 'rescue' tool - a well planned and though-out solution should avoid the need to use it. IF or when you have to use it - always fully test the solution for any unexpected behaviors (dropped constraints) immediately afterwards.

 

  05 Degrees of freedom (DOF)

[07:54 / 7.45MB] All about understanding, adding, removing, testing and reporting degrees of freedom in a DDD solution.
From the Help File:

...ambiguity in a design is summed up by a number called "degrees of freedom." Each new construction adds degrees of freedom as follows:

Construction: Degrees of Freedom Added
Point: 2
Line: up to 4
Circle: up to 3
Ellipse: up to 5

Each valid constraint removes one or more degrees of freedom.

A well-constrained design has zero degrees of freedom and no redundant constraints. All constructions are well-constrained.

If the number of degrees of freedom is not zero, then parts of the design are under-constrained.

When a constraint is added, the remaining degrees of freedom are displayed, followed by the message "OVER-CONSTRAINED" if there are any redundant constraints.

And if all that sounds confusing, don't worry it is! The best way to understand DOF is to get stuck in and experiment with some simple tests.

 

  06 Symbology and Definition

[04:57 / 4.77MB] This video continues directly on from the previous discussion on Degrees of Freedom, and looks at how MicroStation displays visual feedback through element symbology as to the status or ‘definedness' of your working solution.

The language of DDD is one of the biggest hurdles when developing an understanding of how to get the most out of it. It would probably cause more confusion by trying to ‘invent' new, more meaningful and less abstract terminology.

So instead, once again, I recommend to ‘learn by doing'. A little experimentation and a few ‘A-HA' moments later and all the concepts of MicroStation's implementation of DDD become very clear... from that point on it becomes plain sailing.

 

  07 Getting Help

[06:58 / 9.96MB] As I have mentioned a couple of times already, explaining and understanding the abstract concepts, or the mental angle-of-attack assumed when preparing to work in DDD is fairly subjective. For the reader or viewer here to tune into my explanations may be easy for some and not-so-easy for others.

If you find anything discordant so far, why not read about the DDD from another's viewpoint? This video talks about a few different resources available (that I know of) and should be helpful if you get stuck on any point or need more clarity.

By the way, if anyone knows of any other resources that I have missed, please leave them in a comment, thanks!

Here are hyperlinks to some of the resources mentioned in the video:

http://discussion.bentley.com/  (will be eventually superseded by this webspace)

ftp://ftp.bentley.com/pub/help/tutorials/

http://srv.emc.ufsc.br/~altamir/Emc5364/docs/ms95/Tut13.pdf

 

  08 Dimensional Constraints - Part 1

[06:05 / 6.59MB] This video describes the first of three methods for adding dimensional constraints to a DDD solution, namely: Adding a Variable while placing a dimension

On a side note, another procedure was shown here: copying a DDD solution. It's worth noticing that DDD solutions should be copied using the Clipboard as opposed to MicroStation's Copy Element Command. Go ahead, try both methods out and taste the difference! 

 

  09 Dimensional Constraints - Part 2

[07:34 / 9.54MB] The second and third methods for adding Dimensional Constraints... converting dimensions to constraints and assigning variables to dimensions.

And a little info on variables, constants and naming conventions.

 

  10 Dimensional Constraints - Part 3

[08:56 / 10.3MB] Looking at the various types of dimensions that can be assigned as constraints, which make up three main groups:

  • Distance
  • Radial
  • Angular

Then describing a selection of the most suitable dimensioning tools for conversion to constraints.  

 

  11 Algebraic Constraints - Part 1

[07:34 / 8.97MB] Unlocking the endless possibilities and power of DDD though the use of Algebraic Constraints, at the very least, standalone Algebraic constraints solutions can serve as saved calculations that might be repeatedly punched into your desktop calculator. In other cases it can replace those spreadsheets and give you direct access to complex calculations right in your design environment, saving window-switching multiple document management and tracking.

But the ultimate use is when assigning these outputs to Graphical Solutions for prototyping designs and generate final presentation output all in one shot.  

 

  12 Algebraic Constraints - Part 2

[08:02 / 10.0MB] Following up in this video with a couple of common and practical examples:

  • Assigning a variable to multiple dimensions (to achieve equal divisions or symmetry)
  • Constructing an arc that can be driven by length using equations.

And as a bonus, I make some errors in forgetting to make dimensions associative while placing, which might help with trouble-shooting.

 

   13 Attaching Graphics - Part 1

   14 Attaching Graphics - Part 2

[07:28 / 8.97MB] [06:52 / 8.77MB] Attaching Graphics is the last piece of the Jigsaw when building a DDD solution.  

 

  15 Automation - Part 1

[09:58 / 12.6MB] Automation is a very important and sometimes very useful part of DDD. A good understanding of how it works is very beneficial to the solution builder.

This first part starts by comparing some sample steps taken for the manual method with the Automated method. Then I go further with a second example and compare how automated constraints can make less efficient choices than might be desired by the designer. Finally a quick look at the Constraints Tutor which is found in the Profile tool palette and includes the Convert to Constraint and Sketch Profile tools.

As I tend to repeat many times, I'm not a huge fan of Automation for real-world works in complex solutions. I would also recommend not becoming reliant on Automation, because if something goes wrong - a good understanding of the manual is needed for trouble-shooting and repair.

 

  16 Automation - Part 2

[09:45 / 13.7MB] This video takes a deeper look at comparisons between Automatic and Manual solution building with 3 different methods:

  • Manual
  • Convert to Profile (auto)
  • Sketch Profile (auto)

This is also probably the first opportunity to see a ‘completed' solution in that it includes all presentation graphics, constraints, driving dimensions and presentation dimensions and an ‘anchor'. The solution also includes some Symmetry - which can only be added manually.

The result of this comparison demonstrates that even on the simplest solution, Automatically placed constraints can number about 150% more than a solution that was built manually.

 

  17 Automation - Part 3

[07:38 / 8.57MB] The third video on Automation is a quick look at some of the ‘other and miscellaneous' tools in the DDD toolboxes, some of which don't always get a lot of mileage - but for the sake of completeness in this series described here as best I can:

  • Break Constrained Geometry
  • Trim Constrained Geometry
  • Fillet Constrained Geometry
  • Chamfer Constrained Geometry

Two little extras at the end of this video... they don't really fit to well anywhere else but are quite important and used all the time.

The first is a look at Describe Constraint which is the little Microscope Icon (I think!) found on the Evaluate Constraints Tool Palette.

The second and most important describes how set or change the size of all Constraints widgets as drawn on screen by MicroStation. Hint: Found under the Sketch Profile and Convert Element to Profile tools in the Set Text Size Automatically area.

 

  18 Special Constructions

[07:02 / 8.23MB] There are 3 types of Special Constructions in MicroStation's DDD toolbox:

  • B-Splines
  • Constrained B-Splines
  • B-Spline Cells

B-Splines are like LOCKed elements (no degrees of freedom) and can have points Constrained ON them.

Constrained B-Splines can have their ‘knots' constrained by other Constructions in order to change the shape of the B-Spline, but canNOT have points constrained ON.

B-Spline Cells CAN have points constrained ON, and can also have a directional constraint, tangential constraints and point (from its center), but canNOT have their ‘knots' constrained.

...watch the video and it all become clear :)

 

  19 Dimension Driven Cells

[05:11 / 5.38MB] Placing a DDD solution as a cell (using the DDD Cell tool palette, keyin: DDCELL TOOL) opens up a few more functions to us.

It allows us to place the cell with or without constraints and designate each variables values before placing the cell graphics into the design file.

If we remember from an earlier video, I mentioned that to Copy and DDD solution - use MicroStation's clipboard; alternatively you could create and place cells if that is more suitable.

Another item to note is that all DDD solutions are automatically assigned to a Graphic Group which can be useful when deleting a cell from a collection of overlapping but independent DDD solutions.

In the video I also go through the other tools available from the DD Cell tool palette. One useful one is Drop Driving Dimension, although the normal technique here is simply delete the dimension, this option might get you out of a hole at some time.

Lastly there are a couple of tools in the DD Cell tool palette which don't work for me, DD Cell Origin and Attach DD Cell, for unknown reasons.

UPDATE: While I still haven't located the root of my problem with DD Cell Origin and Attach DD Cell, Sam Wilson from Bentley has been able to test and report everything seems to be working fine in the latest Athens release.

 

  20 Rounding - Part 1

  21 Rounding - Part 2

[06:30 / 9.10MB] [06:04 / 7.09MB] This video is about Rounding values that are retrieved from Expressions, similar to round, roundup, rounddown, ceiling, floor etc in Microsoft Excel. However, we only have a much much shorter list of options available to us in DDD - and even those are not documented as part of DDD.

So a little bit more manipulation is required, while this video (and the next few following) are not necessarily about the tools in DDD, they are about some advanced methods we can use in with DDD in order to get even the most from it.

Another tip that gets thrown into the video...

Don't use the word processor to edit DDD expressions. For more reliable performance, if you are finding expressions won't get applied to solutions properly, it may be that there is some unusual character encoding blocking it from getting processed, instead use the Dialog Box to place and edit text.

And this dull math gets followed up by possible practical example of where Rounding might become useful in real-world designs.

 

  22 Conditional Formatting - Part 1

[08:06 / 9.41MB] To present some Conditional Formatting in the DDD solution, another little bit of Math is employed. I prefer to use Conditional Formatting to give visual feedback during the design to let me know if I have exceeded design limits. But not to restrict me at the same time.

There is another (simpler) method, which will prevent or limit expressions from returning values outside of a specified range, shown in the video too.

This first video shows the theory behind Conditional Formatting, the next will demonstrate how to set it up with Graphics in a design file.

 

  23 Conditional Formatting - Part 2

[09:46 / 11.8MB] Following on from the previous video, an example of Conditional Formatting Driving Graphics in the practical example.  

 

  24 Min and Max

[05:26 / 5.76MB] More Math...
How to return either the minimum or maximum values by comparing the results of two different expressions... again, I have found this unassuming little ability VERY important - DDD would be practically of very little use to me, if I couldn't do this.   

 

  25 Table Lookups - Part 1

[07:00 / 8.59MB] This video demos a technique to simulate Table Lookups. At a stretch we could think of this as a simple if, then, else construct.

This is MicroStation's DDD at the limits of my knowledge, and it's fun too! BUT is very very useful as well. Don't all Engineers love empirical formulae and Tables upon Tables of values when designing? Why not let MicroStation look them up for you?

It is a combination of many behaviours and techniques described already, nothing new, just putting them together in a different way.

 

  26 Table Lookups - Part 2

[07:43 / 9.31MB] This final video follows on from Table Lookups Part 1 to complete the set and complete the whole series on Dimension Driven Design in MicroStation.

 

And Finally... 

 Here's the DGN File [593KB] used in the recording of the videos, if you're looking for it.

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