MCAD Tech News (#286)

15 Jul, 2010 By: Cadalyst Staff

Avatech Tricks Tutorial: Verify Fit with Autodesk Inventor Tolerances

Use a digital prototype to determine whether real-world parts will fit together as they should.

By Anthony Dull

Calculating tolerances has always been the hardest part of design in my experience. What happens if "Part A" tolerances go to the high side and "Part B" tolerances go to the low side? Anyone can model something on this magic box we call a computer with exact dimensions where everything fits beautifully together. The defining moment is when you have the parts in your hands and everything goes together the way it should. If not, the solution is not to get a bigger hammer — it is to use your Inventor digital prototype and explore various "what if" scenarios with your tolerances until you are satisfied that parts can be made.

In this example, we are going to enter our tolerances directly to the sketch environment as we place dimensions, as well as inside the assembly file to verify there will be no interferences between parts. As you can see in my skeletal model, I am using the "multi-body" design concept. To ensure that the design updates correctly as changes are made, consider using any skeletal modeling technique.

Testing Tolerances

Inside the sketch for the door extrusion, let's add a tolerance to the width. To do so, edit the dimension and click on the arrow to the right of the edit dimension dialog box. Then, select the tolerance option. Apply the appropriate tolerance for your design, close the dialog box, and finish the sketch.

Now let's go and test out our new tolerance to see how it could change our design. Open up the parameter dialog box and find the dimension you just added the tolerance to. (To find parameters more easily, rename them to something that will help you locate them later on.) Under the tolerance column, change the value from nominal to upper, lower, or median and view the changes to the model. We are now one step closer to verifying that our digital prototype is ready to be manufactured. Read more »

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Anthony Dull is a mechanical applications engineer for Avatech Solutions.


First Look Review: ATI FirePro V5800

Mid-range graphics card is economical, energy-efficient, and an excellent choice for AutoCAD users.

By Ron LaFon

AMD recently added several new products to its ATI FirePro series of professional graphics cards, among them the high-end V8800, the entry-level V3800, and the mid-range V5800. Cadalyst Labs opted to test the ATI FirePro V5800 to gauge the performance of this middle-ground option. Those wanting more performance and memory could opt for the V8800, and those desiring a more economical card could go with the V3800. Since AMD's initial announcements, the company also introduced the ATI FirePro V7800 and V4800.

Features and Specifications

The ATI FirePro V5800 features 1 GB of ultra-high-speed GDDR5 memory and a native 30-bit display pipeline in the graphics-processing unit (GPU) to ensure accurate color reproduction and high visual quality in a single-slot graphics card. These characteristics make the V5800 well suited for CAD and digital-content creation (DCC) users who work with medium-to-large models.

The V5800 is based on a new-generation GPU that features ultra-parallel processing architecture to help maximize throughput by directing horsepower wherever needed. This intelligent management enables real-time rendering of complex models and scenes and increasingly greater frame rates for animation. The V5800 has 800 stream processors, one 128-bit memory interface, and a 64.0 GB/second bandwidth. Read more »

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Ron LaFon is a principal at 3Bear Productions in Atlanta and a contributing editor for Cadalyst.


Mark Your Calendar: MCAD Events


July 25–29, 2010
Los Angeles, California
SIGGRAPH 2010 — the 37th International Conference and Exhibition on Computer Graphics and Interactive Techniques — will include a three-day exhibition of products and services from the computer graphics and interactive marketplace. Read more »

The Best of V-Ray
July 28, 2010
Los Angeles, California
The Chaos Group, in partnership with CGschool, will present a live, full-day V-Ray training workshop at SIGGRAPH 2010. Read more »

CIMdata PLM Certificate Program
September 20–24, 2010
Oslo, Norway
This assessment-based certificate program from CIMdata, a product lifecycle management (PLM) consulting and research firm, prepares PLM professionals to address the challenges inherent in PLM implementations. Read more »

For a complete list of CAD meetings, conferences, training sessions, and more, check out our calendar of events on Are you hosting an event that you would like to include in our calendar? Submit details at least two weeks in advance to


What’s New at


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Members of the new Facebook group have some advice for their fellow CAD managers. Read more »

Cloud-Based CAD, Part 1
What is cloud computing, and does it make sense for CAD users? What are the risks and benefits, as compared with installing software on desktop machines or serving it through local area networks? Read more »

Event Report: Siemens PLM Connection 2010
Product lifecycle management — with a high-definition twist — takes center stage at user event in Dallas. Read more »

About the Author: Cadalyst Staff

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