Plane to cube help and sizing too please before I do more

I have looked in the other threads and couldn’t find what I needed so far.

I am designing a model train for Australian modellers. Instead of designing in plastic and molding/casting it, I thought I would give the 3D modelling a go. I am a newbie to 3D modelling in a CAD program so please ‘go gentle’ and explain in beginner terms! Haha. I am usually quite literate with the computers and have just started using Blender 2.69.

I started with the base as a plane. I extruded this up to form the walkways and get the correct height and curves at the front. I have drawn a couple of cubes to do the long hood and the cab. When I ‘select all’ by pressing A, it selects all the cubes but not the plane. I don’t want to go too far yet until I know that I have started right.
Does this matter when I come to 3D printing? Will it print this plane too?
If not, how would I get the plane to turn into a solid object like a cube function so I can select all of the areas at once? Basically like a copy function but change it from a plane to a cubed item. Will I have to retrace it using a new cube? I will also later need to hollow out the middle of the train so it can fit over the chassis I have for it, and not sure if the plane would hollow too.

The other question I have is that I have imported the plans as a background so I can work off them easier. When I rotate the item so I can see it better, I know that I have to go back to ‘top’ to get the plans back so I can continue, and I have found the quad view too! When it comes to the size of the model to be printed, I need it to be exactly 112mm long. Is there a way to tell the program that the walkway from end to end is to be that size? I have a friend with a 3D printer and he just gets the STL file on an SD card, plugs it in and it starts printing. I don’t want my model to be huge by mistake.

I hope I have made myself clear for these questions. :confused:

John.

Are you in edit mode when selecting all of them?

When you add an object in edit mode it becomes linked to the exsisting object.

So lets say you had a cube in your scene. You selected the cube and the clicked into edit mode. Then shift A and add another cube. The second cube and the first cube will be linked together. So now you would be able to press A to select all.

When modeling a scene in my opinion it is better to create seperate objects then join them later.

How do you create seperate objects enter object mode. Make sure no objects are selected. Then shift A.

From your posting it seems like you may be going about what your trying to do the hard way.
Ill tell you something someone told me when I first was trying to learn Blender. “Blender is here to work, your here to tell it waht to do.” “Most of the time what your trying to do, Blender has a feature, or combination of features that can do it for you.”

So look at some tuts, check out Blenderguru.com, look for Johnathan Williamson Tuts.
Something you may also look into is using a reference image. using a ref image and a morror mod can make life a ton easier

Search you tube there are plenty of tuts on ref images.

Hope this helps

Thanks. This is what happens when you try self teaching!
If I’m in edit mode, I can select either the cubes or the plane, but not both at once.
However, in Object mode I can select everything to move as one, which is what I needed!
I also found that the plane is in a red, and the cubes are in orange. Is this so the user can identify which is which?