Le monde est petit, I'm Gemnoc on the same forum. We exchanged a few replies about FreeCAD in the "conception mécanique" topic.rockn wrote:I am peterp@n on forum.ubuntu-fr.org
To export to pyBar the steps are to make a list of nodes and the decomposition of line.Yorik wrote:Your red drawing makes me think of this: imagine that we have a structural construction, like your truss here. What would be a smart workflow to export it to pyBar? Select all the elements, press an export button and that's it? Probably not, because the code that would export might do wrong guesses about where and which bars to intersect.
Code: Select all
X3 | | X0----X1-----X2
Yes there is some concept to implement, I think of the concept of type of ends of structureYorik wrote:So we would need an intermediary step. Collect all the elements, and create the pyBar scheme, and possibly change or adjust the nodes.I was thinking first, the Drawing module could help with that, but maybe it would be a good opportunity to implement something more generic, a general way of defining intersection points between structural members. This way, the day someone wants to implement something else than pyBar, part of the work is already done.
Very interesting.. They face the same problem as us. Yesterday I've been thinking: "And if we do the contrary? If you must first draw a big sketch, then place a structural element on each line of the sketch" but that seems a bit rigid... No way to easily move the individual elements... And also that wouldn't be very practical for non-planar situations.rockn wrote:I learn Autodesk Robot Structural Analysis a few years ago. It's a really huge gaz engine.
Basically we need to draw a wired model in space, and define each element (material, dimension, type of connection at the ends, service class, what checks are to do). An exemple of liaison between elements in Revit and the export to Structural Analysishttp://youtu.be/YpD8DAeWl6E It's hard to find It is difficult to find information about the operation of the softwares.
Like I have say I have created the example above with starting to draw the fiber neutral line and place the Arch Structure elements after.Yorik wrote:Very interesting.. They face the same problem as us. Yesterday I've been thinking: "And if we do the contrary? If you must first draw a big sketch, then place a structural element on each line of the sketch" but that seems a bit rigid... No way to easily move the individual elements... And also that wouldn't be very practical for non-planar situations.
Yes I think about it too. Like armatures we can add an Intersection properties to arch structure object. We have to manually select all entities that intersect the first element and then we can have a signal if node/line are not coincident...And then we can modify those nodes and give them arbitrary locations like you says.Yorik wrote:But we could do something a bit like in the revit video: a structural member (when it is based on an extruded profile), defines 2 nodes automatically (that would be the two endpoints of an extrusion line that passes through the center point of the base profile). But you, as the user, would have the possibility to modify those nodes and give them arbitrary locations. So it would be your responsibility to set these points correctly if you want intersections to be calculated. Later on we can of course imagine some helper tools to help with that.
But I also think, in your example above, that the object X0-X2 should be aware of X1... That could be interesting later (for example export it alone, and apply a force at that point). We could then imagine the structural nodes of an object as an array of points... You could add as many as you want. That could also be useful for example to approximate arcs...
Very good start !!!Yorik wrote:This seems a good start to me. We could add to structural elements something like the sketch grid... Some visual widget that you can turn on/off, that would show the structural nodes and lines of an object.
Yes, I don't know if I use the right terms in english.Yorik wrote:Can you clarify what is recessed and relaxed nodes? These concepts are new to me
Got it perfectly! Thanks!rockn wrote:Yes, I don't know if I use the right terms in english.
Recessed or Not Relaxed is an assembly like a weld so there is a transfert force lever arm. There is no degrees of freedom.
Relaxed is an assembly made with only one bolt (for exemple) so the elements can rotate. There is the degrees of freedom in rotating axes. But for exemple in timber construction it's usually relaxed liaison that are use even if there 3 or 4 bolts in assembly.
It's a recessed liaison when there is a crown bolts.
Hope I'm clear.