@hieru said: Kaas, I think you would still get good results using your approach if you further reduced the number of circle and bevel segments. The trick here is to use just enough segments and make sure that the block doesn't intersect with the tube along segment edges. Hieru, Thanks for your reply and the trick you mention. I'm going to test it soon.

Thanks For all your words of advice I very much appreciate it. Thanks for the link Edson, It is the reason why I have been so late in coming back, I have spent a good few hours watching the clips. I have moved the model nearer to the origin and can zoom in and out ok now. I have split the 4.1km scheme into 10 segments so I will have to figure how to join them up again. diolch yn fawr Stephen