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Hoe to create a "rolled steel" arc or circular steel section form a Bricsys profile

I want to create a curved/rolled structural steel section. When i assign a profile to an arc drawing object created in Bricsys the resulting bim Beam object is always segmented. U want a pure arc object which is what is needed if we have a rolled steel section. How do I do this?


  • The FACETRES system variable controls the display of curved faces of solids. The higher the value, the smoother the display is, but large values have a significant impact on memory usage and performance. Use the REGEN command to apply the new value.

  • Please notice that the spaUserFacetRes user preference must be ON. Otherwise a default tolerance will be used.

  • edited December 2019

    Worth saying that curved solids are constructed differently from a simple 2D Circle (or Ellipse) which are purely and continuously curved as an expression of a regular geometric equasion. Irregular 2D curves and all curved 3D solids are constructed as a series of straight segments.

    Why can't curved solids, if extruded on a true Circle or Ellipse baseline, also be pure and continuous?

  • As far as I know extrusions of an arc or a circle are saved internally as arcs and circles, it's only the display that is segmented. When you cut through such solids the result are true arcs, solids, ellipses, ...

  • Can we get confirmation on this? I think when I took a plan section the rolled section was drawn as a true arc. However visually in 3D it is a Polyline, Also, I am concerned about how this 3D rolled section is represented when exporting to a client as an IFC or other 3D model. I’m pretty sure other programs represent rolled steel 3D object sections as pure arc geometry
  • Also, how is the intersection handled by the structure connect command if I want to intersect two rolled pipe sections? Will the tessellation cause an inaccuracy? Seems like if I try to detail steel rolled sections there will be issues in the model as I could be intersecting with the segment solid of a polyline instead of a true arc.......
  • I have trued to join a straight hollow steel round section to a curved/rolled hollow steel section using the structural connect command and it does not work.

    1. the axes for the rolled/curved steel member are not visible
    2. the structural connect command does not work.

    If i do the same thing but have a straight beam element instead of a rolled the operation works correctly. It looks like curved/rolled beam behavior is very limited.

  • FlowConnect does the job: see movie in attachment.

    876 x 676 - 951K
  • Interesting but doesn’t answer some other main concerns

    1. Please test it when you are attaching not to a straight member but to a curved member created from an arc
    2. It is still not possible to create a steel bricsys bim member from a curved member - the beam axes are not available on a curved beam and you cannot create an offset for the arced beam member with respect to to the offset beam property. It seems like bricsys beam elements can only be applied to linear geometry
  • I played a bit with curves and arcs and assigned Profiles.

    They behave indeed a bit strange.
    - Can't select end Faces by Marquee ?
    - Can't connect them
    - Can't extend them along their radius

    and such things.

  • Yes this is my point. They also have no beam axes and you cannot reassign eccentricity. Compare to a beam member created among a linear polyline. Gain it seems like unless a beam is to be constructed along a linear geometry, it is not possible
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