StCAD8.1 was created on 2009/10/15. It is a minor and partial update of StCAD8 to run in VW7.7. The STCAD site http://www.ar-cad.com/products/stcad.html has a 'How to Install and use StCAD' video at http://www.askoh.com/stcad/installStCAD/index.html The video starts with downloading parcels from the stCAD site. The VW7.7 distribution includes stCAD8.1 (in the folder contributed/StMath), so you already have the parcels. Follow the video from the point where you are instructed to load parcels. (Note that 'StDoc' in the video has been renamed 'StWord'.) Alternatively, do the following: * In the VW7.7 Launcher, do System > Load parcel named ... StCADStart (this loads the contributed/StMath/stcadstart8.pcl parcel and others) * Loading the parcel executes 'StCAD.Editor open', launching freeCAD. Inside 'freeCAD' * click Explain/Quick Test/, Explain/Quick Start/ for instructions and tutorials. * click Explain/About/freeCAD/ to locate the creation date: freeCADx was created on yyyy/mm/dd. (You can Verify that you have the latest copy by comparing with the creation date published at http://www.ar-cad.com; also check you have the latest patch.) 3D CAD Framework for Smalltalk, A-S Koh (notes taken by Niall Ross; talk given at Smalltalk Solutions 2004, Seattle, 3 - 5 May 2004). =================================================================== Askoh has been working on StCAD for over five years. In 1987, he worked on Motion Simulation in dynamic simulator system ADAMS. After he lost access to ADAMs, he tried various languages and in 1989 found Smalltalk. In 1994, he built OODS plus AutoCAD, which impressed ADAMS so much they bought it, replacing his simulator component with ADAMS. He released freeCAD in 1999. FreeCAD lets you define 3D assemblies of 3D parts (simple rigid solids) connected by joints, constraints, dampers and special forces (e.g. position dependent forces). You draw parts, run simulations, and then interrogate re what forces were exerted at specific locations, etc. Askoh ran a demo of a steering joint example, with shock absorbers, springs, dampers, etc. He ran the demo, zoomed and rotated, etc. He then haloed the joints, selected one and called up plots of various behaviours (to display data, it uses the VW business graphics object kit, to which he has added zooming and other features). An engineer who wants to explore an idea is the target audience. 80% of engineering ideas can be explored here to determine their viability before you buy some extremely expensive software for further analysis. He showed how you would draw up an assembly. In a 3D view, he chose a plane (XY) to constrain the initial drawing and then extruding it to the Z dimension. He added various joints (circular, pin). All these joints are effectively expressing mathematical constraints graphically. He added a motion to that joint by customising a template, then set a step counter and animated, then got results plot for the joint. Next, he added a second part, a wheel, again by adding a circle in a plane and extruding it. He assigned mass and suchlike details to it, applied some markers to points on it and set up a pin joint from his first model trapped inside the wheel. He resumed animation, to see how the wheel behaved, then added gravity and showed how it now behaved, then plotted torque. There is no collision detection at the moment; he is working on it since engineering-wise it is useful. He would like to improve the UI (i.e. the displaying UI; the user’s UI for driving it seemed fine to me, the displaying UI fine for an engineer but of course nothing like a game rendering engine or whatever). A given state can be saved in a text form that is readable by a spreadsheet (where you could change the data by hand or by formula and reimport). He can also generate a POVray file for each step, letting you animate in POVray. Separate motion, shape, etc., files let you replace shapes in POVray yet keep the motion. He then showed a 3-planetary orbit simulation, a JCB digger simulation, a collision example (puck on seesaw, using coefficient of restitution to determine collision behaviour.). He then showed an actual consulting job he did of a barge at sea, affected by waves, placing an oil platform on its supports using water ballast to raise and lower itself. Finally he showed a few classic engineering examples, spring system, cantilever beam and wobble pump air compressor (large example needed 15 parts and 20 joins). StCAD is free for download on the web. • The graphical code is basic and open source • The geometric domain code is basic and open source. He is adding OpenGL graphics (using some stuff from Jun) and showed us a preview; better solids look. • The numerical handling code is good and open source. He has welltested powerful matrix algebra and solvers, differential equation solvers, and general Newton-Raphson. He also has a symbolic mathematics parser and differentiation. • The multi-body handling code is advanced, and not open source StCAD has been used for advanced motion simulation and is ready for solid modelling. Smalltalk made him very productive. Q. Rendered by? Smalltalk graphics in everything shown (can use POVray as described). Q. Who downloads? People in Boeing, US Military, Nasa and similar, plus many university downloads. Q. Smalltalk is fast to code in; how fast is it to run? Fast enough for me. Simulating a full car would no doubt be faster in an up-to-date version of ADAMS than here but this is fine for real requirements. Q. Visual Editing, e.g. select a part and resize? Yes but with a ‘do in 2D then extrude to 3D’ style as this is using a 2D package I have expanded to 3D but not seamlessly in all its capabilities.