How to make multilines follow a polyline?

Unknown said:

Is there any way to automatically place a multiline along a given path?

Is there a way to place anything, such as a line-string, along a path?  I don't know: what do you mean by a path?

Unknown said:

We have to consider other utilities' underground piping

So a path is the space between other existing objects?  A GIS tool might term that a corridor?  An electronics designer might use a routing algorithm.

No need to be philosophical about terminology. I'm not familiar with English CAD terminology so I just translated the German word into English. As I already wrote beforehand: I consider a polyline being a "path" - or is that not the correct CAD term?
I'm not looking for automatically finding the ideal corridor for our piping (there's way more to consider than just available space), I just want to make the other utilities' 2D drawings ready for us to do our design work in an easy way. I. e. add the correct outer diameters and safety margins to the provided simple line or polyline. Quite often there' s e.g. a pipe with an outer diameter of .5 m and a safety margin of 1 m to be added to both sides which is displayed with a single line with weight 0. So instead of placing gazillions of parallel lines or tediously placing a multiline along that "path" it would be great if there was a Microstation standard means to either change such a polyline to a multiline or just making a multiline follow a polyline by selecting start and end of that line.

Great idea, Ian! I'm familiar with creating custom line styles. If only the line style editor window was a _little_ bit bigger...

This solution has only one drawback for me: I usually assign a layer to the safety margin that won't print.

Here's an example of what I do with multilines. Maybe that helps understanding what I'm looking for. The advantage of multilines over custom line styles is that individual elements can be assigned to different layers with different line styles, colours and weights that can easily be changed when needed.

Maybe it's not easy to program or implement, who knows. Multilines are such a great tool I'd love to see enhanced, e. g. by adding filling with hatchings or only certain areas and being able to assign transparency/priority to individual elements (especially the filling).

Thanks George, I was well aware of the plot/noplot issue with custom line styles. However, I believe a linear pattern won't do the job as good as a multiline as it's too inflexible for my purposes. I wouldn't know how to make a pattern follow a polyline anyway.
I guess I'll have to stick with my standard procedure until Bentley comes up with some enhancements (i. e. I expect no change within the next 10 years...).

as long as your line (smart line) doednt have any curves or arc you can just trace over your work ...

However there was a VBA macro published by Rod Wing  at Envision cad to convert stings to  multilines...

It even worked to some extent with curves by turning them into multiple straights and provided your print scale is high enough you want  notice it .. if you ask Rod really nicely he may let you or the forum have a copy if his company  wont let him I'm sure it could be bought for a very modest  fee.. 

I was lucky enough to get  a free copy when it was being given away but I dont think it right to share it without their permission...

Thanks heaps, Lorys. That might be worth a try, I'll contact him and see how it goes.