Dimensions in drawings are either:
True. Accurate model values.
Projected. 2D dimensions.
The dimension type is set when you insert a drawing view. You can view and change the dimension type in drawing view PropertyManagers.
The rules for dimension type are:
SolidWorks specifies Projected type dimensions for standard and custom orthogonal views and True type dimensions for isometric, dimetric, and trimetric views.
If you create a projected or auxiliary view from another view, the new view uses Projected type dimensions, even if the original view used True type dimensions.