In Civil3D it can get confusing knowing what layer is controlling what and why, especially if you are just starting out in Civil3D. So lets take a brief look at how layer control works in Civil3D.
The best way to think about how layers are controlled in Civil3D is to think about how layers are controlled in a block. Lets say you have a block made up of three objects – a circle, a line, and a polyline. Each object making up the block is on its own layer and the block is assigned a layer. In our example, we have four layers that now control objects that make up this block.
If you freeze the CircleLayer, then the circle INSIDE the block object will disappear.
If you turn off the the LineLayer, then the line INSIDE the block object will not display.
If you freeze the BlockLayer, then ALL the objects making up the block are frozen.
You get the idea.
In Civil3D, the objects are made up of sub-components.
For example, an alignment is created by adding sub-entities (lines, curves, and spirals). So think of each of these sub-components as having the possibility to be on its own layer and being able to control the SUB-components simply by controlling their layers.
If you freeze the AlignmentLineLayer, then the lines that make up the alignment object will disappear.
If you turn off the AlignmentCurveLayer, then the curves that make up the alignment object will not display.
If you freeze the AlignmentObjectLayer, then ALL the objects making up the alignment are frozen.
The similarity to blocks does not end there. Just like blocks, if a sub-component making up a Civil3D object is on layer “0” then that sub-component will take on the C3D object layer’s characteristics.
So much control, which means more options, which means more potential for confusion. Hopefully, this helps break down layers a little bit in Civil3D.