Need help in Photoshop

[Leafblower]

Hey everyone

I'm in the process of building my own cabinet, and I wanted to make my own artwork aswell.
I have a simple knowlagde of Photoshop, and I'll be watching some guides aswell.

I'm using the "Project Mame" build from Rasmus Kønig Sørensen.
http://www.koenigs.dk/mame/eng/draw.htm

I wanted to make a "template" or "outline" of the cabinet sides, and controlpanel in Photoshop, so I know which parts will be on the cabinet and which parts will be cut off.
I was planing on making the image about 10 cm. bigger in both directions, so I have 5 cm. of extra artwork, all the way around. In case I did'nt cut it 100%. 

But sense the sides isn't 1 big square, and I don't wanna risk my artwork not fitting, I wanted to make an outline of the sides and controlpanel, so I know where what goes, once I actually print it.

However I can't seem to figure out how to draw in Photoshop, while being able to tell Photoshop how long the lines are.
If I need a line to be 50 cm. I have to draw by free hand, and how to land near 50 cm.
I want to be able to draw a line, click it and tell it this like has to be 50,00 cm.

Is this possiable? Or is there a better way to get my "outline".

Hope someone can help 

[JDFan]

Sounds like you need Rulers and/or guidelines ( you can place a new guideline at any horizontal and/or vertical spot in the file and it will place a line either horizontally or vertically at that spot across the file so then you have a reference line to show the start and endpoint you want.

[Malenko]

make a new image 50cm long and 5 pixels tall. fill it in black. Copy paste it into the artwork image as a new layer. BAM 50cm line

[opt2not]

make a new image 50cm long and 5 pixels tall. fill it in black. Copy paste it into the artwork image as a new layer. BAM 50cm line

This.
Quickest easiest way. No fussing with lining up guides/rulers.

[thatpurplestuff]

Assuming you are using Photoshop CC, another option is to use vector shapes... for example you can select the rectangle tool (under the same menu as rounded rectangle, ellipse, polygon, line and custom shape) and then draw a rectangle.  Before you do anything else, if you go up to the very top you can adjust the width and height of the rectangle... I can't remember what the default unit of measurement is but you can right click either field and select between pixels/inches/centimeters/millimeters/points/picas.  Just type the exact dimensions you want and there you go... the nice thing about this method is that you can change the dimensions at any time by selecting the layer and hitting ctrl+T, then entering new dimensions in the same place that you did when you created the shape.

Technically you can also transform a raster shape once it has been created like the above recommendations, but having it as a vector will make it a bit more precise since you don't have to worry about things getting pixelated or edges being softened if you transform it to be much larger than it was originally created.

[Leafblower]

So I've finaly figured the outlining of my project out, and am now working on the controlpanel.

I would like to create en effect around my buttons similar to that is used on the Coldbeamgames - Borderlands 2 cabinet.
http://www.coldbeamgames.com/cabinet-artwork-download.html (Top picture)

I've tryed with several bevel and emboss + shadow/glow guides, but I can't seem to make it look right.
My theme is more classic arcade and 8bit-ish, With a blue color theme.