Developing Good Modeling Technique

We are seeing more modeling coming from those within the Architectural Industry using Revit so I thought I would talk about some basic concepts to help develop good modeling technique. In the past I have seen the results of poor modeling technique coming from the Manufacturing Industry using Inventor, Solid Works, etc.... The basic concepts I’m referring to can be applied to both industries as a means to develop good modeling technique.

What I am talking about is applying constraints as you make your model and the use and applying the two different types of constraints; one being dimensional constraints and the other geometric constraints.

• Dimensional constraints are exactly what it says they are dimensions that you apply to your model. These dimensions can be just a number or a parameter or equations.
  
• Geometric constraints are the constraints such as collinear, align, etc... These constraints will tie your sketch together without the need for dimensions.
  

When creating your model the first technique you need to do is to tie your model together with geometric constraints - I cannot tell you how many models I’ve seen in the past with dimensions at a 0 value. What I have tried and found to be extremely helpful is to use dimensions that are required on the drawing - Believe it or not 99 percent of the time these are only the dimensions you will need to put on your model. I also want to point out that using geometric constraints also creates a clean model which makes it that much easier to update in the future.

Another important concept to keep in mind is to make sure that your models are fully constrained - which results in predictability when making changes to your model. Just imagine putting your model in a project file and when you try to change a parameter, the results show only half of the updates you thought it should have. That is always the result of a model not being fully constrained.

The final basic concept you should keep in mind when creating your models is to test, test and test again. Do not be afraid to test while you are creating your model and again, after you have completed your model.

Dynamic block arrays

In the past week I have noticed a couple issues come up dealing with arrays, or truthfully trying to do advanced handling of these arrays within the dynamic block itself.

Unfortunately Autodesk has some work on creating equations and variables inside the block editor so you could do some what ifs and such.

You could try and create visibilities to handle different scenarios that you are trying to accomplish - but this can get into a management issue of your block and size constraints and manual operations to select the correct visibility.

You could get into creating a separate dynamic block of the array in question and inserting it as a nested block. If these are small blocks that will be inserted multiple times, this may not be a suitable option. Nested dynamic blocks work best on large dynamic blocks that are inserted 10 times or less into a drawing.

There are a couple approaches that I feel should be taken or at least looked at:

Event:
One is creating an event that will watch for changes in your dynamic block and then change the array parameters in question. This is not best suited for real time changes and you would see the changes after you are completed.

• This would require creating a list of all the potential blocks to watch and what you want to do with it
• Creating a standard, so the list can be appended by the Cad manager - not hard coded

Jig:
Another is using what is called creating a jig - using dot net. You can set up using a jig to see real time activity. As you make changes to the dynamic block you can see the array changes in real time. From the user and the interaction with dynamic block, this might be the best approach.

• The best approach here would be to create a command that will allow you to insert the dynamic blocks - this can be set up to handle all of your dynamic blocks and put the parameters right on the screen next to the block as you position it.
• Create another command that would allow the changes and see them real time.
• This would require creating a list of all the potential blocks so you know which blocks have the arrays to manipulate
• Creating a standard, so the list can be appended by the Cad manager - not hard coded

Dynamic blocks have brought some power of parametric's to the AutoCad user but still has some limitations. When you combine it with dot net, the power increases 10 fold and allows you to do so much more.

Let me know what you think or feel free to contact me.

Patrick K. Johnson

Retrieving New Part Number(s) using the Vault / Product Stream

Are you using the Vault, Product Stream (Vault Manufacturing) and getting frustrated when you need to go somewhere else to pull a new part number for the part or assembly you are designing within Inventor or for that matter, within AutoCAD? We can show you a new way to use the Vault and/or Product Stream to your benefit.

CAD Enhancement Inc can create an add-on tool that allows you to pull a new part number and rename your model with it. The way this tool functions is while you are working within Inventor and have your model up on the screen (either as a separate file or in place within an assembly), you will have the capability to pull the next number available and rename your model to this new part number. You can also define as many schemas (part number structures) as you desire to complete your processes.

If you do not use the Vault and/or Product Stream (Vault Manufacturing) or any comparable product this can be done quite simply by providing a database file that could be utilized in the same manner.

Feel free to contact CAD Enhancement, Inc to inquire about the possibility of creating this tool for your Engineering Department.


Patrick K. Johnson