Avatech Tricks: Creating Lofted Solid Bodies with Inventor v117 Jul, 2006 By: Rob Stoklosa
New lofting and G2 surfacing capabilities help you get the most out of your AutoCAD and DXF files.
There's a lot of buzz around town regarding the new lofting and G2 surfacing capabilities introduced in Autodesk Inventor v11. In this article, I discuss a few of the methods and techniques used to create lofted solid bodies with fairly complex rail systems. Incorporated into the demonstration are some great tips and tricks on getting the most out of your AutoCAD and DXF database of files.
I will use an imported DXF file of a commercial airliner to construct the fuselage with the aid of the lofting functionality. I also will present a brief demonstration of some of the upcoming lofting-to-a-point capabilities of Autodesk Inventor.
First I imported the DXF file (figure 1).
Figure 1. Importing the DXF file.
After I have the imported data, I need to separate the individual views into their own independent sketches and center them about the 0,0,0 origin. To accomplish this task, I create additional sketches and use the Move command from within Inventor's sketch environment to center each sketch. (figure 2).
Figure 2. Independent sketches of the imported data.
Next, using the project geometry function, I project points from the existing DXF sketch onto my active sketch plane. I then use this sketch and the spline tool to create the spline that defines the nose section of our loft (figure 3).
Figure 3. Project points from the existing DXF sketch.
After all the lofting sections are complete, I focus on the rails that will eventually define the overall shape of the loft (figure 4).
Figure 4. Side view of sketch.
Here, I have all four rails completed using a combination of 3D sketched entities and properly positioned work planes (figure 5).
Figure 5. Completed rails.
I can begin the lofting function. Here, I have three sections and four rails. All four rails combine together to form the 3D oval shape of the fuselage. Using the loft feature, I select my sections and define the path. Rails can be found in the lofting dialog box, and they essentially provide a 3D path for the loft to follow (figure 6).
Figure 6. Lofting to form a solid body.
I now continue implementing the same techniques to complete the rear portion of the fuselage (figure 7).
Figure 7. Same techniques applied to form the rear fuselage.
Using the new lofting-to-a-point technology with G2 curvature capabilities, the nose completes the complex shape of the fuselage (figure 8).
Figure 8. Lofting to a point.
All of which results in the final product. Below I use the rendering capabilities within Inventor (figure 9).
Figure 9. The completed lofted sections.
Autodesk Technical Evangelist Lynn Allen guides you through a different AutoCAD feature in every edition of her popular "Circles and Lines" tutorial series. For even more AutoCAD how-to, check out Lynn's quick tips in the Cadalyst Video Gallery. Subscribe to Cadalyst's free Tips & Tools Weekly e-newsletter and we'll notify you every time a new video tip is published. All exclusively from Cadalyst!