Skeleton Modeling

Skeleton modeling is a design method that can be used for both single parts and assemblies. The idea is simple. Draw a skeleton sketch, or several sketches that locates the important surfaces and maybe even the base feature sketch. Once you have located all the important surfaces that sketches will be placed, you can begin building your part. With this concept, you want to use either linked dimensions to your feature extrudes and cuts, or extrude up to next/surface. This way, if your part changes size, you can change the skeleton sketch and your features will adjust their position. You may still need to make detail changes (chamfer or fillet sizes, cut or extrude sizes), but the repositioning work will be done for you.

Start with a basic skeleton on the front plane:


Add another arm on the right plane:


Add your required sketch planes at the endpoints of your arms:


Begin extruding and cutting your features:




Your basic part can now be detailed with flanges or other finishing touches:


When your part changes, the skeleton is changed and everything will adjust:


For an assembly, the process is the same. Make a base sketch at the beginning of your assembly that includes axis' and points placed at insert positions. From there you can place any required planes and begin inserting parts and attaching them to your base sketch as well as to one another. Any changes in the assembly size can be updated in the base sketch. This is a very effective method for companies that create dynamic parts from an assembly model. Some companies have reasons to tie the designer's hands and restrict this practice. My company prefers to hang us in the dungeon by our thumbs.