CAS Modelling stands for: Computer Aided Styling. It is where you sit with a designer and make a quick, simple, model from his/her sketches. You use very low degree curves and surfaces. This enable the designer to request changes, as you go, which are easy and quick to do, because the model has direct active memory.
This Alias CAS module will teach you how to build a model quickly, which is ready to export from Alias as an IGES file, to send directly to CNC Milling. CAS Modelling (Computer Aided Styling). Is used a lot in the modern Automotive Design Studio. Many of the skills you will learn are listed in the description of of the CAS modelling process below:
A CAS model is created in a short time, from the sketches and ideations of the designer. This means that he/she will see you frequently to give directions on the model. A CAS model is a light file, because it is built with degree 2 and degree 3 surfaces, which in turn are built on a curve structure. The curves can be as low as degree 2, but for complex lines such as the shoulder degree 5 curves can be used.
You will learn how to model surfaces manually (Direct Modelling). You will learn
how to become a Virtual Sculptor.
It is important for the modeller to keep the direct history of the curves and srf alive, so that the model can be lengthened, shortened et cetera, using the Transformer Rig. When the transformer rig tool is employed with live history, all the curves and srfs that are affected by say stretching the model will automatically update.
CAS modelling requires the modeller to form a closed volume as early as possible into the build. The main reason for this, is that the designer could ask you to export the IGES file of the model and transmit it to CNC Milling at at any point. The model will then be milled from a clay slab built over a wooden and polyurethane armature. After it has been milled in synthetic clay, a clay modeller will make further changes to the design. Next the clay model will be scanned and you will be sent the .STL file (Mesh Data), so that you can continue developing the model in Alias.
A CAS model is a SHARP model. This means that the srfs show the Theoretical Point of Intersection. So there are no radii applied to areas such as the shoulder and body side intersection. This allows for modelling to occur faster and changes to be made quickly without the complications of having to update blend and fillets. NB: when blends and fillets are applied to srfs, they lose their direct history.
You will learn how to retain your model as a closed volume. This will enable you to stitch it and then make a shell. This shell can then be exported , as a STEP or IGES file and sent to CNC milling to turn it from a virtual model into a real physical model.