Multiple continuous Arcs

[tgarchitect]

Hello

 

The building I am working on is the shape of a jelly bean. The exterior glazing will be segmented and we are trying to make the building as dimensionally uniform as possible. IE 5'-0" Curtain Wall units. So each arc length needs to be perfectly divisible by 5'-0" and the transitions from one arc to the next must occur at a tangent point.

 

Any ideas on how best to draft this out. Eventually we will be developing the building in Revit 2013 but for now we are in ACAD 2013.

 

Thanks in Advance!

 

Toben

[JD Mather]

Investigate the Parameters tab.

You might also look into Measure and Divide commands.

[tgarchitect]

Thanks I was able to constrain the arcs to be tangent to one another. Now just need help on the arc length uniformity of 5'-0". is there a different CAD software out there that this type of drafting might be better suited for?

[Tuns]

So you want to draw any arc with any radius possible but the arc length has to be divisible by 5'-0"?

[tgarchitect]

We have the building drawn, but now are being tasked with making it dimensionally efficient, cost effective, and constructable. If all the curtain wall units are 5'-0" wide then it will be easier for the contractor to build. Some of our arc lengths of the jelly bean are close to being divisible by 5(off by a 1'-0") but others are right in the middle. IE a arc length of 77'-6" or so. We can flex the shape of the building to make the shape constrained by the tangents to the arcs and each arc to be divisible by 5. I am quite skilled in CAD but I do not know the best way to modify the line work we already have other than trial and error.

[Tuns]

Well if I were you, I wouldn't touch any of that and let whoever is making the curtain walls figure out what is best. It is their job to do that after all. If you change anything it might lead to a whole new problem. I'm in the architectural precast business so believe me when I say that. I've seen even the smallest changes make a huge problem. If you want though I can try and figure out how to do what you ask for future use.

[tgarchitect]

Thanks Tuns, I think there is enough descrepency between the arc lengths that are currently shown and what we want them to be to warrant further analysis. We need to have a better idea how making the arc's divisible by 5 will affect the form of the building as it will have a ripple effect through the interior architecture and structural systems. We are in schematic design for the next 3 months so we have time to figure it out.

[Tuns]

Sounds good. Don't let them rush you; those contractors (from what I've seen) push the architects to throw out drawings and they start construction before you guys are even done drawing the thing... It aggravates me to no end to have to go back and make changes because the architect finished about a month after construction started at the site...

[JD Mather]

... If all the curtain wall units are 5'-0" wide ....

 

It is unclear to me whether your constraint is Chord length or Arc length?

[eldon]

The exterior glazing will be segmented

 

When I did a bit of setting out for a curtain walling firm, the glazed units were straight.

 

So perhaps the chord length is what you should be watching, not the arc length.

[rkent]

Once you have the shape drawn with arcs use bpoly to make a continuous pline. Then break that at a logical location to control where the first curtail wall panel would start, set pdmode to 3, then use measure and 5' as the distance. You will have nodes every 5' along the curve. Continue from there.

[eldon]

Another point to consider is that if the exterior face does go in a series of straights, the position of the tangent points is not an over-riding consideration.

 

Thus a unit spanning from one radius to another would not detract from the appearance, and you would not have to worry about arcs being so exact.

[rkent]

Rather than worry about the length of an arc I would make a block of the panel 5' long, then using measure on the continuous pline or spline, specify that block, and a length of 5'-1" for the spacing in the measure command, or what ever works depending on the overall size of the building.

[tgarchitect]

Thanks all. I have made the overall length of the jelly bean the required length so that when I divide the length of the polyline by the amount of glazing units, the CHORD length is exactly 5'-0".

[Tuns]

Thanks all. I have made the overall length of the jelly bean the required length so that when I divide the length of the polyline by the amount of glazing units, the CHORD length is exactly 5'-0".

Don't forget the radius. Would make it way easier if you provide a radius.

[eldon]

Don't forget the radius.

 

I am not sure when I last saw a curved glazing panel. Nowadays they all seem to be straight - I wonder why

[tgarchitect]

I am not sure when I last saw a curved glazing panel. Nowadays they all seem to be straight - I wonder why

 

Curved glass is VERY Expensive. You would really only use it for high end interior spaces, lobbies, board rooms, etc.

[Tuns]

Curved glass is VERY Expensive. You would really only use it for high end interior spaces, lobbies, board rooms, etc.

So why mention arc length if your not using curved... anything? Or is the contractor actually paying for curved glass?

[RobDraw]

Good points. If it's not being built with curved pieces then the jelly bean is only a guideline.

[JD Mather]

So why mention arc length if your not using curved... anything? ....

 

See Response #9 - I think the OP was confused about how make the actual problem statement.

 

Arc is relevant, arc length, well that is only a reference - not a driving constraint.