Create a polyline arc that mimics the shape of a building

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Hi there all,

I am new here so forgive me if my question is vague or likewise is a bit over the top.

I have been sent a client's construction drawing for a care home where i need to design the sprinkler installation. The majority of the rooms have got the same head positions within them, but they have all got a slightly different angle as the building is shaped like a banana. Unfortunately its not a uniform radius that i can tell as the one side is larger than the other.

So my question is this. Normally, on a square building, I drop in construction lines along the bedrooms so that i know my sprinkler heads are all the same distance off a wall, and I only need to line up one side. However, with this building being a curve, and the wall angle being slightly different on each room, how do I place an angled construction line or polyline to act as my set out line for my heads.

Ive been looking at the drawing and various forums now for the past 2-3 hours and still haven't seen an answer that helps greatly.

Richard

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How about offset to the construction line layer? You will have to do it for each room since they are different.

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I did think about doing that to be honest. Once i do that, is there any way to make the line a smooth radius as oppose to the straight lines of the walls?

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Can you please post a screen shot of the main walls? I cannot quite understand your description of the geometry

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Here you go Eldon. Hope this better explains it.

My corridor head positions need to be central between the bedroom walls you see so follow the curve of the building, my pipework is then typically offset from these at approximately 600mm to one side of it so i need to be able to draw this as a single line for each corridor section. The pipework is going to be bent on site and therefore the drawing needs to show it as true also for other trades coordination.

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I would start by drawing some arcs. The arc can be drawn by picking three points along the same face of a wall, i.e. at the start, at a point near the middle and at the end.

Once you have got the arcs, then you offset them wherever.

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Right, just to update you all on how I have done it.

I looked at doing it how Eldon has suggested with the three points for an arc, but due to how many line changes the client has got (each wall is a straight line and joined to look like a curve), i have followed each joint with the spline tool to give the smooth curve of the interior walls on the corridor. I then offset this by the equal distance for the centre of corridor. This however gave me another spline with undreds of points on it which i kept on altering everytime i tried to click anywhere near it. I therefore drew over the new spline with an arc, start, end, direction, and changed the centre point to be on the spline and give the correct curve.

This may be a very long winded way of doing it but i am quite happy with my results and have plotted sprinklers and pipework today on all three levels. Just got the tedious task tomorrow of adding the dimensions!

Thanks for your help. I'm happier now using Cad knowing that there is an online community that is friendly and helpful.

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Have you tried creating a polyline for the building wall and offsetting that? Then use PEDIT with the FIT option to curve it.

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oooh, thats a good one! I will try that tomorrow morning and see how that fairs. The trouble is the way that they have already drawn it and sent it over. Be much easier if they drew it with a curve aswell instead of hundreds of little straight lines! Makes the file massive too.

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oooh, thats a good one! I will try that tomorrow morning and see how that fairs. The trouble is the way that they have already drawn it and sent it over. Be much easier if they drew it with a curve aswell instead of hundreds of little straight lines! Makes the file massive too.

Best of luck.

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Right, just to update you all on how I have done it.

I looked at doing it how Eldon has suggested with the three points for an arc, but due to how many line changes the client has got (each wall is a straight line and joined to look like a curve), i have followed each joint with the spline tool to give the smooth curve of the interior walls on the corridor. I then offset this by the equal distance for the centre of corridor. This however gave me another spline with undreds of points on it which i kept on altering everytime i tried to click anywhere near it. I therefore drew over the new spline with an arc, start, end, direction, and changed the centre point to be on the spline and give the correct curve.

This may be a very long winded way of doing it but i am quite happy with my results and have plotted sprinklers and pipework today on all three levels. Just got the tedious task tomorrow of adding the dimensions!

Thanks for your help. I'm happier now using Cad knowing that there is an online community that is friendly and helpful.

After drawing the spline, pick it and right click on the mouse, convert the spline to a pline, use a small number like 3 when asked. Now use that to offset, etc. If you need it smooth then use pedit with FIT option.

Edited by rkent
changed spline to fit

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