Best Free CAD Software Tools Free CAD Programs2. D vs. 3. D CAD Software. The most important distinction to keep in mind is between 2. D and 3. D CAD software. In the olde days when designers and architects stood pen in hand at the drawing board, they designed in 2. D. Early CAD software emulated this, displaying only trite top, front, and side views in 2. D, and some CAD programs to this day only display 2. Soap_Bubble/images/bezier1.jpg' alt='Bezier Curves Sketchup Plugin Export' title='Bezier Curves Sketchup Plugin Export' />D. Believe it or not, for functional designs many designers even prefer 2. D CAD. As a rule of thumb, 2. D CAD software is geared towards simple technical geometry. D is always an abstraction of the real thing. So, it is not an ideal tool to explore many alternatives of complex designs. This is where 3. D enters the picture. SketchUp Plugin and Extension Store by SketchUcation provides free downloads of hundreds of SketchUp extensions and plugins. This Instructable will show how to use the SketchUp to Inkscape to Ponoko Laser Cutting pipeline with a little plugin that Ive written. Only with the advances of GPUs, 3. D rendering became a commonplace feature that enabled new tools that had been impossible on the drawing board. This allowed engineers and designers to create more complex geometries. The most radical development probably is 3. Win 7 Alien Sp1. D sculpting. 3. D CAD software enables complex technical geometry, and designs since 3. D representations are less prone to misinterpretation. Also, physical simulations are easier to implement and interpret. As 3. D modeling grew out of 2. D technical drawing the line between the two is often blurry, as most CAD programs feature modeling tools from both worlds. In our list, you will find the full spectrum of free CAD software Solid Modeling vs. Surface Modeling. Many free CAD software boast solid modeling as a key feature. Whats so solid about a computer file Solid models supply information on physical properties like the center of gravity, volume, and mass. The idea behind the solid model is to represent a given object completely to be able to physically manufacture it. Usually, you will start with primitive shapes cubes, spheres, etc. A surface model on the other hand only consists of a wireframe, and data describing the surface. These can be free form surfaces like Bezier curves or NURBS surfaces, and others but it contains no information on the models content. Surface models are sufficient for many applications, like 3. D animation, graphic design, and even 3. D printing. Of course, youre not stuck with either one or the other. Most free CAD software allows you to convert between solid, and surface 3.