RS Components released it first PCB design called DesignSpark PCB in 2010. So, what's the good of it? Let me give you some description about it below.

The million dollars question would be 'which software would do good to answer the needs of those engineers?' Welll, I won't be giving an answer for that particular question, but I will surely show you one potential software series from RS Components, a UK company. Some others could also create 3d models/parts and still come for free. There are some free drafting software which are quite useful to create 2D layout drawing. Double and triple clicks help you select closed paths and solids in 3d.The same situation within engineering design area. Just some common things which cannot be restored from videos: To move camera around selected object you need to hold middle mouse button pressed and to shift camera - hold also Shift button. Videos are without narration, but I tried to make them short and understandable. I've made these three video tutorials to share my experience of using common tools and some useful tricks. Once you have downloaded and installed it from the download page you can start your experiments.

Still it's quite a powerful and easy to use tool, which I consider to be the best available free CAD modelling tool. In fact it's a limited version of SpaceClaim Engineer. That's why when I found that DesignSpark launched free DesignSpark Mechanical modelling software I was just excited. Unfortunately, professional CAD software is expensive. Not saying that to 3D print you just need to model it in some design software. It can save your time and resources and give you certain insights on improvements of your initial idea. It's generally a good idea in DIY(and not only DIY) projects to model your future device in 3d before start actually making something.

Designspark tutorial