Ask HN: How to mock up physical products that don't exist?

I think this is what CAD software is for?

1. The physical product - it is actually a good idea to take a simple piece (you can just take a piece of wood like the inventor of the Palm Pilot did) and do an improvisation theater with it. For this you explain to a user what it does and hand it over to them and ask them to explain to you how they use it.

2. The visual mockup: For me the best results have been to do a simple 3D model and render it with Keyshot - there are rendering alternatives called Bunkshot and some others. Basically these are 3D Rendering programs that very easily allow you to assign materials to a product and create a high quality render very quickly without having the very complex and advanced knowledge required to do a VRAY render. Regarding the 3D model itself a good start is Sketchup, formerly owned by Google.

Do you need an accurate model (from an engineering standpoint) or just a visual representation of the product?

If you don't need a complex model, you can use a simple 3D tool like Google SketchUp. That would probably be the easiest solution. If you've got a little money to spare, there are plenty of CG artists that can work up a model for you and render it in a photo-realistic manner.

Using good old pen and paper or adobe ideas are a good starting point. Don't worry if your sketches look like crayon scribbles by a 3 year old, the act of putting your thoughts down will likely lead to more thoughts/tweaks to the original idea. And the more you do this, the better your design skills will get. After that, and acknowledge that you had said not to actually build it, I'd move to putting together a basic prototype with any parts that you can get your hands on - trade/building supplies/art and craft store/daiso/discount store etc. The benefit of doing this is that once you/potential customers can handle the product, you'll learn more than any visual mockup will provide and the design will likely change again. Going through this cycle several times will lead to a much better design.

List of visual mock up tools (free and paid): http://i.materialise.com/creationcorner http://www.shapeways.com/tutorials/supported-applications

From an engineering standpoint, digital prototyping is a huge time saver when mocking up products.

If your product will be under some physical stress it is good to understand where the weak points exist and how to negate them. If manufacturing costs will be a major concern (eg plastic parts, tooling, and mold design) then you need to know how to reduce them.

Autodesk Inventor is a fairly easy to use option. Ansys is much better if you need to simulate how it will react in the real world and have a fat wallet for their licence costs.

I just built a book press out of bubinga and stainless; Prototyping it in Inventor allowed me to see where the weak points were in my design and make modifications that allow it to work beyond the typical load required of a book press.