Aligning circles

[brakware]

I am trying to array a tubular extrusion. The problem is that if I try to align the tube while in sketch mode (creating the extrusion), then, when I try to array the tube, it says that the group is constrained to something outside of the group and either I need to remove the constraints or cancel the operation. This means that I have to constrain the first item in the array and the second/last (respectively) item after I array the object. Tricky thing is, though, that I cannot align my tubular extrusion to anything because I cannot align the center to anything after I am out of sketch mode.

My thought on a solution was to make the object a separate family and nest it in the current one, then I could have symbolic lines or reference planes to align to, but for the family that I am building, I need to complete all the pieces of it, and then do a void cut over all of the objects so that it is in a wedge shape. Void cuts will not cut nested families (or at least, when I tried briefly to do it, it wouldn't work).

Does anyone know of a solution for this, or has anyone run into this problem before? I have spent a lot of time on this family, and it will save us tons of time in the future if I can get it right. If anyone has any suggestions, I welcome them. Thanks in advance.

[aaronrumple]

Select said circle. Go to the properties and turn on the "Center Mark Visible" Use align. Have a nice day....

[brakware]

Tried that. Once it is extruded and I am out of sketch mode I cannot align the center of the circle to anything.

[sbrown]

put some ref planes in or make a symbol line with the center marks turned on.

[jamie.casile80054]

aloha,
could you post an image? i'm having a hard time visualizing what you're trying to accomplish.
-jamie

[luigi]

Since it sounds like it is from within an inplace family, have you tried adding 2 ref. place that intersect the circle (Center L/R and Center F/B) defining origin....then the center will be selectable and alignable




Tried that. Once it is extruded and I am out of sketch mode I cannot align the center of the circle to anything.

[aaronrumple]

Tried that. Once it is extruded and I am out of sketch mode I cannot align the center of the circle to anything.
You align the circle while in sketch mode to a ref. plane or other object.

[brakware]

This is not an in-place family, this is a stand-alone "generic model" family.

I cannot constrain the circle while I am in sketch mode, because, as I said in my original post, if I constrain it while in sketch mode I cannot array the extrusion outside of sketch mode. I also cannot array the circle while in sketch mode.

I cannot constrain the resultant extrusion to anything (reference planes, reference lines, symbolic lines) that I can later constrain to something because Revit is not giving me anything in the extrusion to constrain to other objects with. Also, if I could constrain it to something like a reference plane/line/etc., I would not have a problem. Revit will not let me constrain the extrusion to anything that helps me, even to a circle of the exact same size.

Because I need to array the extrusion (so that the number of the array can adjust to spacing and length), I cannot try to constrain any part of my extrusion until after I have arrayed it. At such point I can only constrain the first object in the array, and the second/last (respectively) object in the array.

I will try to put together an image of what I am trying to do to post it.

[aaronrumple]

Like this.... You use old school Revit circles in this case. This technique has a lot of other applications.

[brakware]

I am running 8.1. The family you sent says that it was saved in a later version and cannot be retrieved.

[brakware]

Here are some images of what I am trying to do. I have a thatched roof section that I am trying to build. There is a thatch surface, and on the underside of it I need to run battens that will rest on rafters. After I have created the thatch, the battens, and the rafters, I am going to drop a void cut onto this to make it into a wedge shape. This wedge will then be nested into the complete family where it will be arrayed in a circle to make a polygonal roof where the user inputs the radius of the roof, the slope of the roof, and the number of sides to the roof.

Since I am going to void cut the whole wedge, I have to have all of the objects that I am going to cut as part of the same family. If I nest anything (like the batten), the void will not cut it. I cannot even explicitly tell Revit to cut a nested family with the Cut Geometry tool.

Since the overall length and slope of this roof section is going to change, depending on user input, I am going to have to do the battens as an array. If I try to put them in individually, I would have a massive set of boolean statements and constructs and parameters and whatnot in order to have them go into place properly... and even then, I would have to have a cap to how big the roof is instead of having it infinitely scalable.

Please take a look at the images, and thanks again, in advance, for any help that I can get.

[aaronrumple]

Sorry - I no longer have 8.1 installed. Basically what you do is make the circle of two arcs. This gives you an endpoint that will align.

You can always download 9.1 and run in demo mode to look at things posted here in later versions. Pretty soon it will be 2008.

[brakware]

I tried the two arcs approach already. Actually, Revit gives me some snaps as though it were created with two arcs when I create it with a circle. The problem is that the snaps that Revit gives me do not help. If you take a look at my image "Thatch_Roof_Goal.gif" you will see that I need to center the circle on the intersection of the grey cross. What you can't see is that the nested family of reference lines has reference line circles, as well. I cannot align the arcs, the circles, or the centers at all once the circle (or double arc) has been extruded.

The problem with aligning the two arc endpoints that it allows me to align with is that the circles are going to array at an angle. To determine my center in the family "Thatch_Section_Skeleton.rfa" (refer to image "Thatch_Roof_Goal.gif"), I have had to constrain the lines to the "spine," if you will, that is the roof slope (the thatch slab is constrained to it and is invisible in the views I provided). That means that as the roof slope changes, the angle of the crossing lines changes but the center remains the same. The circle shown in the lower left is permanently constrained to the inscribed cross, as it is not part of the array that I need to build. The orientation of that circle is always vertical, but since it maintains its center position, the circle is tangent to the bottom of the thatch regardless of the roof slope.