GD&T in Precision Engineering : Use of Slots in Precision Location Applications

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GD&T Pin and Slot DRF

Precision location can be very important in various engineering applications, such as machining and assembly. In machining, the tool follows a very precise path and a workpiece must be located precisely and stably at a precise position. In assembly, the positions of assembled parts must be assembled easily and overconstraint of the parts must be avoided. One of the common techniques for accomplishing these targets is the use of slots as part features. Read More

Datum Reference Frame (DRF) in Geometric Dimensioning and Tolerancing (GD&T): An explanation with figures

GD&T DRF Part with Constraints

A datum reference frame is a coordinate system against which the geometric dimensions and tolerances of a part are defined. The main function of the datum reference frame is to specify a foundation for the inspection of the part. It is the common coordinate system of all tolerance zones. Without this common coordinate system, product definition is unclear, rendering the inspection results unreliable. Read More

Comparison of tolerances used for coaxiality control: Position, Concentricity, Circular Runout and Total Runout


Coaxiality conditions can be vital for shafts supporting heavy and varying loads, such as car and truck axles, electric motors, generators and pumps. There are four different types of tolerances for defining coaxiality controls: Position, concentricity, circular runout and total runout. This post proposes brief and practical definitions regarding which type of tolerance to choose for certain applications as well as the advantages and disadvantages to each. For more information, refer to the ASME standard [1] and other related reference articles [2]. Read More

Surface Inspection Annotation

BuildIT surface inspection annotation of points

BuildIT allows users to perform quick and easy inspections. It also enables users to perform analysis and produce reports that are both detailed and simple to generate.

The Surface Inspection Annotation command is a good example of BuildIT’s ease of use. Without performing a complete analysis on a part or an entity you are inspecting, you can evaluate a single measurement at a time. This command also allows you to manually annotate measurements in order to convey information in a way that is clear and simple. Read More

GD&T for Beginners: MMC & Bonus Tolerance, Explained in 3D

GD&T 2D vs 3D

Geometric Dimensioning and Tolerancing concepts are often difficult to grasp at first;  beginners can have quite a difficult time understanding the basic principles. One of the reasons for this difficulty is the visualization problem of 3D concepts in 2D documentation.

The goal of this blog post is to analyze the effect of the MMC (Maximum Material Condition) concept on a pin (shaft) in a 3D context with a simple example (Figure 1). Our example replicates the case in the Figure 2.15 in the ASME Y14.5-2009 standard (page 33) in a 3D context with much larger tolerances (and errors) to better visualize the concepts. Read More


Figure 4. .obj model opened in Meshlab.

Photogrammetry, despite sounding rather complex, is basically  the stitching together of a series of photos to obtain a 3D model. In this post, we will analyze the results of a 3d model provided by Autodesk Recap 360. This post will just be a simple example; we will delve deeper in future posts for more detailed analyses. Read More

Surface visibility, shading and transparency

Diagram of BuildIT Wireframe Types

In BuildIT, the visual representation of surfaces can be customized in various ways to suit your needs. Here is an overview of the multiple ways in which we can use surface visibility to customize the representation of the model we are working with.

When selecting a surface, either from the Object Manager or directly from the Viewport, we can find its Rendering Mode options under the Surface tab. Read More

Essential steps to filter between CAD objects in BuildIT

View objects in NoShow

Last week, we saw how to make use of the Show and NoShow Views in order to unclutter a CAD model and work more efficiently by using these two layers in an optimized way. In this article, we will use the NoShow View to differentiate between various elements of the model in order to take them out of Display or delete them altogether to make our model more responsive. As mentioned in last week’s article, the View toolbar menu contains three useful options to send elements to the NoShow View. Let’s review them quickly: Read More

Work Clutter-Free Using the Show and NoShow View

Hinge Detail View in NoShow

When performing an inspection, it’s always nice to have a clean workstation and an unobstructed view of what we are working on. In the same way, having good visibility within the CAD model is important in order to work efficiently. A good way to achieve this with BuildIT is to make use of the Show and NoShow Views. Read More

Tricks to Customize the User Interface

Display Object Manager Right

By default, the Object Manager, the Command Window and the Process tab are grouped in the panel located on the right-hand side of the screen. Most users want to have their options displayed that way (Personally, I do), so here is an easy way to put it back in place if it is ever accidentally displaced. Simply hold down the panel’s top bar and drag it to the positioning arrows that appear on screen. Read More

Handy Tips for Importing Models

BuildIT Select Coordinate System

There are two ways to add a model in BuildIT:  Open and Import.  While the Open command flushes any open model before adding the new one, the Import command will simply add the file to the current working one, making it very useful to merge different files together. BuildIT supports a wide range of CAD formats which can be imported in this fashion, including BuildIT files (*.buildit extension) Read More