STL Import and Shape Defor­ma­tion: Latest Work

Some of our cus­tomers use CAESES® for shape opti­miza­tion of existing geome­tries, we some­times refer to it as a par­tially para­met­ric approach. Typ­i­cally, a geometry gets imported into CAESES®, using one of the various STL formats. The geometry is then deformed by a set of shift trans­for­ma­tions or free form defor­ma­tions. So far, this works excel­lent, con­sid­er­ing the fact that free form defor­ma­tions have been added to CAESES® just some months ago. However, in several sit­u­a­tions we felt that there is still a lack of aux­il­iary func­tion­al­ity for which we needed a rather com­pli­cated workaround to realize the task. Finally, we came up with a set of new little things on our wishlist in order to make the design process easier. Here is a selec­tion of the things that we have recently added to CAESES® — we’ll make it avail­able in version 4.0.4: 

Shortest Distance

We needed a way to set up con­straints such as the shortest distance from one part to another, to keep track of a minimum distance when doing shape changes. An auto­mo­tive example is the require­ment of a part not to violate the instal­la­tion space. Hence, our trimesh (that’s the object that contains the geometry tri­an­gu­la­tion) now offers a new command for cal­cu­lat­ing the shortest distance. In the fol­low­ing short video, we wrapped the command in a feature def­i­n­i­tion for better usabil­ity. With this, we’ve got the distance value for setting up a con­straint, and the shortest con­nec­tion is also visu­al­ized in the 3D view with a simple line object.

Open Edges as Curve

Open edges of imported STL data are now directly avail­able as a 3D curve. We wanted to have this for the purpose of setting up the bspline boxes of free form defor­ma­tions, where bspline boxes surround the geometry region that gets changed during an opti­miza­tion. As one option, any 3D curve can be used as path to generate such a box, i.e. the box creation can be under­stood as a simple sweep along the 3D path. For STL data, we can now simply grab one of the open edges and use it as an input path for the bspline box. Without this little piece of func­tion­al­ity, we’ve had to set up such a 3D curve manually, this was really a boring task. So now it’s just there! The fol­low­ing video shows an imported STL geometry from which an open edge is directly taken as input path for a bspline box: 

Split By Angle

This is another wish that imme­di­ately comes up if you cope with STL data in a CAE-software: A simple way to split the given data into several pieces, based on a user-defined angle. This allows users to receive the inlet and outlet patches sep­a­rately, for instance. These patches can then be indi­vid­u­ally colored and used as input for the CFD meshing process. It also makes life much easier for our free form defor­ma­tions because you can better select the indi­vid­ual parts that you want to deform, and e.g. switch off the vis­i­bil­ity for untouched parts etc. Applying defor­ma­tions only to a subset also speeds up the defor­ma­tion process because of less input data. To sum it up, there are several benefits of this rather basic split func­tion­al­ity, so let’s simply add it to CAESES®: 

Inter­ested in trying out CAESES® for your appli­ca­tion? Then check out our product pages for all amazing details. Note that we also offer a powerful & free edition of CAESES®, which can be down­loaded from our website. There are no annoying or hidden lim­i­ta­tions, and you can directly start to set up your own intel­li­gent model today! Let’s go — give it a try ;-) 

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