We show how mixing up the way you assign properties such as line weight and color withing the same drawing can make displaying line thicknesses very difficult. We recommend the simple approach, just place entities with thickness property controlled by default. If it is necessary to control lineweight or color, simply change the properties of the entity or move it to a layer and control thickness/color there.
Here is a movie that takes a comprehensive look at the use of lineweights in landscape drawings.
