Basic Question re Walls

[nicolas]

I am new to revit and I have Revit Structure 2015.  I have created the outer wall that that fine. Its 200 mm. wide and everything is ok with that. However when creating separation or partition wall I am having lots of problem with dimension as the wall 150mm. wide is connected to the outerwall and I cannot change one without changing the other.  I want to know whether I can lock the dimension of the outer wall or a way to separate the new 150 mm. inner wall from the 200 mm. outer wall.  I am also having problem viewing 3D where none of the wall appears except the floor while they appears in all elevation views.  Thanks.  

[nod684]

I don't quite get the problem regarding your walls sorry...

 

for the 3D View part where you only see floors, you may refer to this..

https://microsolresources.com/tech-resources/article/top-10-reasons-you-cant-see-an-element-in-revit/