sketchup is awesome. Even the free version. Watch some tutorials on how to use it on youtube, 10 min of video watching will equal lots of time saved when using sketchup. Usually free programs are loaded with bugs, or adds, or don't let you do certain things. The free version actually lets you do everything you need to to make conceptual drawings, and can do it in scale. It runs fast on every computer I have ever downloaded it on and it does not have watermarks when you save your work.
Once you get to know the keyboard shortcut keys you can realistically draw a command box with pretty good detail in under 30 minutes.
One of the biggest tips that helped me when using sketchup was you can enter the size of the shape while your drawing it.
For instance if you know your box can be a total of 38"x 40", all you do is draw a rectangle (keyboard shortcut "R", click the mouse button once and start your shape, and then simply key in those dimensions and hit enter. The box will draw itself.
Then if you know the box can be 30" high, just use the push pull tool (keyboad "p") and do the same thing. Grab your newly formed rectangle with the push of a mouse, "pull" it up, and then key in the height dimension.
Then you can open up the box by using the "F" tool. I am not sure what it stands for, but if you push f on the keyboard, and go to the face of the box you want open, the f tool will draw a secondary rectangle inside the face. The dimension entry works good for this as well. say your material thickness is 1/8" aluminum. You can use the f tool, click the face, ensure the new lines are on the inside of the rectangle, and then simply type 1/8" and hit enter. new lines will be drawn 1/8" away from the outside lines, and then you can once again use the push pull tool and "push" that inside square towards the back of the box. Once again use the key entered dimensions. That back of the box should be 1/8" thick, so you can grab the push pull, click the box and push it in, then enter 39 7/8. this will put the back of the box at 1/8" thickness.
That probably does not make alot of sense now, but again, there are lots of videos on it. the above would take me probably under 30 seconds to draw.
I also love the "download model into sketchup" feature. It allows you to search for things that other people have drawn and download them into your file. For instance, if the box is going into a tahoe, you can find a tahoe someone else has drawn, download it into your file, and then place your drawn command box in the area it is supposed to go. with any luck, the tahoe that you are using will be to scale, and you will have a great idea on if your box fits right.
Also, you can make things a "component" or a "group" and allthough they initially seem like the same thing, there is a big difference. So lets say you are drawing a banister rail. you would start with your simple shape of a cylinder or a rectangle in the width, height, and length of the rails needs. You then select the entire shape, right click the mouse and choose "make component". When you do this, it makes it so you can copy the shape an infinite numbers of times, and every copy will stay identical to the original, even if you make changes to it or any of the copies. So if you made 20 copies of that banister rail, and decide that you want to put some other detail in it, it will change all the copies automatically. if you select and right click and tell it to be a "group" it will be "unique" and will not change based on the original.
My big advice on that is to use the component and group tools for each item. So you will have your outter shell of a box, that should be its own component, then you add drawers, each drawer should be it's own component, handles, hinges, etc. should all be built separate and placed onto the box. This allows you to make changes to the box much easier.
We have used sketchup a number of times to draw conceptual items, and then get them produced. The pro version allows you to save the file in a format that machines and auto-cad software can understand, which makes it a little easier to get something made, but if you have a good fabricator, a simple print of the drawing will suffice.
Everyone should have sketchup. It is a valuable tool. and it is free!
