Face View

[Dave R]

Mike, it's no major hardship to just add guidelines to create temporary intersections along the edge so that the Dimension tool has a snap to point. You can delete the guides when finished with them.

[Mikehd70]

I will continue to use guide lines as i do that in Photoshop ,Acad so i am used to it just not having to find a corner to do measurements.Only started with SU last week.
Thanks again for the help

[Mikehd70]

OK that did not take long,in Acad you can use layers for anything,is it the same in SU.
In otherwords could i put dimensions on a layer so i can make it visible or not

[Dave R]

Yes. You can put the dimensions on a layer or layers to control visibility of them. Just remember layer only control visibility and are not used to keep geometry separate and always, always leave Layer 0 active (radio button to the left of the layer name) and change the layer association after you've made the dimensions or other things. Edges and faces should always be on Layer 0. Components/groups can have different layer associations but don't change the layer associations for edges and faces.

[TIG]

Dave beat me to it, but since I've type this here it is anyway

SketchUp's Layers do not work like CAD's.
Layers only change their objects' visibility.
They do not 'freeze' the objects.
So they do not stop some changes to objects on visible layers affecting connected objects on hidden layers - typically 'geometry'...
If you draw a rectangle and put its face on one layer and its edges on another layer and switched off the face's layer... then you deleted a visible edge and switched back on the face's layer, you'll find that the face has gone too - because it can't exist without all of its edges.
That is why you should ALWAYS create your raw geometry [lines/faces] on Layer0.
Always have Layer0 as your Active-Layer.
Then you make groups or components of that geometry and assign layers to those groups/component-instances.

That way the Layer's visibility hides the 'container', and since there is no connected geometry spanning different layers you will not fall into that trap of assuming CAD-like layer-behavior...

Drawing elements like Text and Dims can be given their own layers and switched on/off, but be aware that changes to visible entities could affect them in subtle ways too - e.g. if you erase the object to which a Dim is attached its color might have changed when you next see it [a Model Info > Dims setting for 'orphaned' dims], and moving an object might unexpectedly stretch the leader of its attached Text when its layer is next made visible... However, it IS common practice to assign separate Layers to Text and Dims to allow you to toggle their visibility on/off - there are even some plugins to automate that for you...