Daily DIY

This tutorial covers the creation of a standard woodworking board or sheet goods part. Since most woodworking parts are simple rectangles or linear sticks, an Extrude Boss will be used create most woodworking parts.

This tutorial is compatible with all versions of Alibre including Xpress.

It is important though to follow certain conventions and standards to ensure consistent part creation and reliable predictable models. Below are some of the most important considerations:

Create Parts and Assemblies with attention to view orientation. The standard Orthographic views of Front, Top, Right and Isometric should reflect those orientations for the Parts and Assemblies. The Front view of a part should be face of a board or molding, and not an edge or end. The Front view of an Assembly should be the front of a piece of furniture, cabinet, or when unclear something reasonable like the face of a bed headboard or footboard. Considering these orientations while creating parts and assemblies will make creation of a drawing easier, as well as provide a smooth and consistent workflow.

Parts and Assemblies should be created symmetrically about the reference planes where possible. There are always exceptions, but you should have a good reason when deviating from this “best practice”. This is a best practice that crosses software brand, and is considered a good modeling technique no matter what vendors software you are using. This will allow you to use the “reference geometry” to constrain parts and sub-assemblies in assemblies.

When creating Sheet Goods parts, we prefer to create those parts with the Length oriented horizontally along the X axis, and Width vertically with the Y axis. This convention has its basis in orientation used in Cutlist and sheet goods layout and optimization programs. It is consistent with working with sheet materials on a panel saw, on saw horses or a workbench, or doing layout work. It also helps when dealing with specifying edge banding. By using the convention of grain running horizontally, from Left to Right when there is a grain directionality, assures consistent material handling and will reduce errors. It will also allow design work to proceed with a consistent understanding of grain directionality and orientation from modeling to construction.

While Alibre does not have material directionality indicators to show grain direction, with this convention you can use the normal arrows from the reference planes to determine face/reverse side and grain direction. Just turn on reference geometry for a part in an assembly and hover over the Planes line item in the Design Explorer to display the normals arrows. We has also begun including a directional arrow on the face of sheet goods parts to aid in properly orientating parts during model assembly. This is a simple arrow shaped line sketch created on the face of the part, and an Extrude Cut 1/64" deep into the face of the part. This indicated Face side as well as grain orientation, and can easily be Suppressed or deleted when modeling is completed.

Lumber can be created with a horizontal or vertical orientation, with a horizontal orientation being common because of sheet good creation conventions. While vertical orientation may be more comfortable when creating legs or stiles, the final orientation of the part in the assembly is determined by assembly constraints to the rest of the model and not the original orientation during part creation. With a little practice, you get used to inserting a part and simply constraining it into position without regard to original orientation, or need to manually rotate the part before applying constraints.

Rather than creating all parts from scratch, we are tending toward using parts saved to a standard “library” parts folder. That way the directional and grain arrow features can be included, as well as a variety of miter features that can be suppressed and unsuppressed as required for baseboards, moldings and other standard uses. We also recommend the “Primitive Wizard” board creation program for Alibre that automates the task or creating rectangular parts (plans.thefrankes.com).

With sketches constructed on the XY plane, a standard board or sheet is Extruded for thickness along the Z axis. While moldings or profiled cross sections are best constructed on the YZ plane and extruded to Length along the X axis. It is a simple matter to orient the display to an isometric view, selected the reference plane on which to sketch, and Activate a 2D sketch on the selected plane. You can then Orient to Sketch plane (if not done automatically) or with a little practice you get used to sketching in an isometric orientation. Remember, construct your parts with consideration to the standard Orthographic drawing views and orientations. It is useful to turn on all the available toolbars.

One last note before creating our board. Woodworking normally only requires the use of a 2D sketch to create even the most complicated of parts. If you are trying to work with a 3D sketch, you should re-evaluate what you are trying to accomplish as it can probably be accomplished in a much easier manner. Besides sketching on the initial reference plans and user created planes, you can use the faces of parts as the plane for a 2D sketch. With Revolve, Sweep, and Loft you can create 3 dimensional shapes using a combination of 2D sketches of profiles and paths.


By: woodknot Source: Instructables.com