PlantUml define relative position of components

I'm actually trying to generate a component diagram with PlantUml. Is it possible to define the relative position of the different components? What I want to define is: ComponentB is left from ComponentA. ComponentC is below ComponentA, ...

A typical approach is to mark a line as hidden.

One thing to keep in mind is that hidden is only supported for left-to-right ->, and top-to-bottom --> lines, so you need to place the left and right side accordingly (syntax X <[hidden]- Y doesn't seem to be supported).

@startuml
class ComponentA

ComponentB -[hidden]> ComponentA
ComponentA -[hidden]-> ComponentC
@enduml

See also How to correct PlantUML Line Path for more positioning tips.

You can follow guidelines from here: Layout of grouping component

In general when you write connections like -> you just have to know that there is special notation for right arrow, left arrow, bottom arrow, top arrow: This has special meaning for plantUml:

 -l->
 -r->
 -u->
 -d->

It means to place arrow on the left or right or up or down if possible.

Lets imagine this diagram:

@startuml
node "My system" {
  [A] -> [B]
  [C] -> [B]
}
@enduml

This looks horrible, you can fix this by directing PlanUml with arrow directions.

@startuml
node "My system" {
  [A] -d-> [B]
  [C] -r-> [B]
}
@enduml

Will generate this: