The Design Process Part Two

At this point it should be nice to have the concept project on paper.  My mind will not sleep if there is a design stuck there until I have it on paper.  This way I know that I will not forget it.  Just a final note on sketches, I write notes on the sketches,  These notes could point out design elements that I feel are important, questions or concerns I have about assembly, things that I do not have quite figured out, or materials needed for the project.
At this point I take my time and put the sketches into a 3D modeling system.  I am lucky enough to be able to use Inventor through my work.  The other popular modeling systems that cost money are Solid Works and Pro E.  The industry standard for the garage shops is Sketch- up.  It is a free drawing package from Google.  There are others that can be found on the internet.  When I first started I drew everything out by hand and to scale.  It was a fun little practice but if I ever made a mistake it was a lot of erasing.
The reason for putting it into a modeling program (or do a scale drawing) is to look at proportions and see how parts fit together.  In the project that I am working on now, I do not really like the caboose.  It looks big but it fits in the design of everything so I am leaving it the way it is.  The locomotive was a different story.  I wanted to be the biggest part of the train but the boiler (which is a purchased furniture foot) was too small.  No matter how I tried to make it bigger it just did not look right.  The wheels didn't look right  and the cabin looked funny.  My final design is a lot smaller but looks good in the series. If I skipped the step of making the scale drawing, I would have been very disappointed and wasted a lot of wood. 
The second reason to make scale drawings is too make prints of the parts.  It is a lot easier to make something after knowing it will all fit together.  Individual part drawings allows me to check off parts when they are cut and it is also easier to figure out what is needed for the project.
The other neat thing about putting a project in 3D space is seeing how it is all going to be put together.  This is where all the problems seem to arise and then get figured out.  Some of the common things that I figure out in the model are:

• Wheel spacing.  The important part of making a wheeled toy is that all wheels work.  They can be all off center but they all need to roll.  From a personal point, I want them all to touch the floor at the same time.
• How parts come together.  There are a ton of different ways of joining parts together.  This is where I decide what joint is going to best for assembly and hide mistakes.  It also helps formulate how the procedure on what parts to make first, when the sanding needs to be done and should I pre-finish parts.
• Proportions as noted above.
• This is also where I figure out how I am going to make each part.  I try to make the parts how I would machine them.  Take the cow catcher on the train, for instance.  I started with a larger block of wood.  First cut the back angle.  Then I drew out and cut the triangle portion on the front.  Through the modeling process I am figuring out how to process the parts.
• The other question that I answer is, can I make this safely?  If I am going to stop a project or go back to the drawing board it will be here.  

This model does not have to be perfect with everything detailed out. I tend to leave of hardware and profiles.  After I am satisfied with the model I will then make prints of each part and put together a materials list.  The drawings will have a room on them to take notes for when the project is going to be put together.  This will lead into the next post and probably the last in this series.