Profile Section Libraries for Structural Engineering and beyond!

B by bernd on 27 Jul 2021, edited 27 Jul 2021 # +1 votes

@Jesusbill said:

Thanks @bernd and @yorik . BOLTS looks interesting, I have to study it.

I would be looking to have more enriched information for each profile; not just shape geometry but also moments of inertia, section moduli, torsion modulus, geometric/shear centre for non symmetric cases, etc., information that has already its placeholders in the ifc schema, too.

So that this information can be directly used in a structural analysis with beam elements for example.

I certainly don't want to reinvent the wheel and prefer to go with the flow if suitable.

I guess the existing libraries of profiles in BOLTS could eventually be enriched. What would you think @bernd ?

Then, we can create also the Ifc Project Library files to use within ifc-specific environments.

I somehow missed this post.

BOLTS is great. The original author has left the project. I did not want to let it die, thus I do maintain it and try to fix bugs and add new sections. But since I do maintain other projects too (mainly FreeCAD FEM) I just do not had the time range to improve BOLTS. It is a pitty the idea behind in great.

I am totally with you in the regard of further infomation like moments of inertia, section modulli ... We just need to be careful if material data is introduced like it is needed for plastic moments etc.

If you would help with BOLTS it would be great ...

Geometry in FreeCAD is created on the fly in python and the data is separated from the code. BOLTS can be connected to any CAD with python interface. I have set up an experimental one for NemetschekAllplan. There are two which works ATM very well, one for FreeCAD and one for OpenSCAD. A connector for BlenderBIM would be cool.

Or the idea you had with IFC ...

We may make a separat new topic just for BOLTS?

cheers bernd

J by Jesusbill on 29 Jul 2021 #

Hi @bernd yes I would like to contribute to BOLTS to extend profile data with other properties that we can then use for IFC project libraries.

I can work on the I Profiles to start with like HEA/HEB/... and IPE profiles and share the list of additional properties to consider in the pure data table, which I feel it would be nice to have it also in a CSV format.

@Moult : thanks for support and advice, I'd say it is better to join forces and figure out the rest on the way :)

B by bernd on 29 Jul 2021, edited 29 Jul 2021 #

@Jesusbill

great news. If you have any questions ask come up here. IMHO it is simpler than on github. If there are more people it will for sure motivate myself to do more on BOLTS too.

cheers bernd

B by bernd on 29 Jul 2021 #

Would you like to be able to get data as csv out of BOLTS or would you like to use csv to get data into BOLTS?

M by Moult on 30 Jul 2021 #

@bernd I don't know much about this, but I think the CSV formats are much nicer to display and edit than yaml :) But maybe not as "rich" structurally so I'm looking at it very superficially.

J by Jesusbill on 30 Jul 2021 # +1 votes

@bernd I have done some work on the I beams, have a look at these commits

What I did was:

Export into csv files all the tables of the selected collections in the "data/profile_i" folder
Validate existing input values compared to data from another source. From these I identified some small differences shown in the first commits
Enrich the csv files with extra column properties

But when I update the blt/yaml file and attempt to write it back I get something much more ugly compared to the existing document and all the comments are lost, is there a specific way you prepare this file?

J by Jesusbill on 30 Jul 2021 #

Would you like to be able to get data as csv out of BOLTS or would you like to use csv to get data into BOLTS?

yes, basically use csv to export, validate, enrich and import back.

I think the CSV formats are much nicer to display and edit than yaml :) But maybe not as "rich" structurally so I'm looking at it very superficially.

Probably for a single table of values, the csv file is the most user-friendly, but including metadata for each table I'd say justifies the use of a dictionary.

The problem with csv starts when you have no 1-1 relational data like a list of properties with variable length.

J by jchkoch on 19 Aug 2021 #

@Jesusbill another package which relates to this thread that I recently re-discovered is sectionproperties which can be used to calculate your sectional properties needed for structural design. Since I was taking another look at the work you have done on I-Beams in the BOLTS project and I'm again unsure whether I like the idea better of a "database" structure for structural section properties or whether calculating these "on the fly" would make better sense. Perhaps it could make sense to integrate a tool like sectionproperties (written in Python) to be used to compute the structural section properties and write these directly as a custom pset for the structural IFC element. As far as I am aware for simple cross-sections (i.e. I-beams, rectangular sections, etc.) calculating structural properties is fairly fast. Another benefit to this approach would be that more complex shapes that might result from parametric design scenarios could be easily accounted for. Look forward to hearing your perspective on this.

J by Jesusbill on 20 Aug 2021 # +1 votes

@jchkoch this looks like a great library! It would be useful to have so as to calculate section properties for any profile.

I do think, however, that it would be better to have these properties already reported for standard steel profiles, or any other standardized shapes of other materials as well.

For rectangular, circular or other simple profiles, it is true that these calculations can be fairly straightforward and most of the times may even not be needed as structural software do cover these cases defining directly only the profile shape and dimensions, or at least this is true for Code_Aster. For symmetric I-beams I have also written this code in ifc2ca to calculate section properties but for most standard I profiles that have also some curved parts these calculations are not exact and I would think it is better to have the exact values already given.

Interestingly Code_Aster has also a macro command for calculating these properties for any shape, but I never used it and it would probably be more complex to implement compared with a python api.

Would you be interested to look into sectionproperties and create a couple of examples so that we can evaluate the code and time needed to do the calculations for a profile? I am definitely in favor of having such a tool available to users.

Thanks for chiming in

J by jchkoch on 20 Aug 2021 #

@Jesusbill I have added the section-properties library on the OSArch Wiki.

It is generally very fast to calculate the section properties for "standard" x-sections (i.e. I-sections, etc.). In my experience using the package 1-2 seconds is sufficient as long as the mesh_size is chosen appropriately (too small of a mesh can cause long calculation times); however, I think because of the flexibility of the library to also deal with complex geometrical x-sections where smaller meshes are needed this is usually a trade-off that is acceptable.

what is the best way to share a couple simple examples? is it best to do so directly on the OSArch Wiki?

J by Jesusbill on 20 Aug 2021 #

Sounds great @jchkoch , a page in the Wiki with a couple of examples could be nice or make a post in the forum?

C by Coen on 24 Aug 2021 #

I see so much resources, but I am confused on how to implement them in Blender straight away with a closed curve which can be used for modelling purposes.

My workflow of getting profiles might be a bit cumbersome, but there are so much predefined dwg profiles. There are a lot on this website

I use ODA file converter to convert them all at once to DXF, then I import them into Blender and set the scale and origin correctly.

The CSV tables in thread might be interesting to make some script with Python which converts all these coordinates to useful curves. Or maybe it already exists? Or some existing add-on?

J by Jesusbill on 25 Aug 2021 # +1 votes

@Coen once we have tables for all standard sections and we can create ifc project libraries that we can import then these profiles will be drawn automatically in Blender. I am supposed to work on this (we started with Moult ~10 days ago) but didn't find the time yet. Let me create this first test library and then we can discuss again.

Regarding the dxf polylines you have created, I tried sth similar in the past but I had difficulty meshing it to create the profile section which could be then extruded. I ended up using Salome to import dxf and convert to a face in stl format which was then imported in Blender.

C by Coen on 25 Aug 2021 #

@Jesusbill

I tried sth similar in the past but I had difficulty meshing it to create the profile section which could be then extruded. I ended up using Salome to import dxf and convert to a face in stl format which was then imported in Blender.

I also extrude the profile sections of the mesh, but I ran into no problems. Please correct me if I'm wrong in my understanding. Or if you see any problems with my workflow.

I imported the DXF and then Blender makes a Bezier curve from it?

Object -> Convert to Mesh. I just get edges

Select all Vertices with A and Pressing F I get the surface

Using the Extrude tool

Will the profile sections/or meshes also contain the structural data that goes with it? For example kg/m?

The tool from DWG to DXF I used make is ODA file converter

Here is the blend file with different dimension of UNP profiles

I am very curious in your approach of getting all the profile sections and getting the IFC data attached to the mesh.

J by Jesusbill on 25 Aug 2021, edited 25 Aug 2021 # +1 votes

@Coen for some reason when I tried it with an I section it was failing at the 3rd step that you show. Pressing "f" was not good enough to get the section mesh as it was creating a mesh that was partly outside the perimeter. Other than that, the approach I followed is exactly what you show here.

I am very curious in your approach of getting all the profile sections and getting the IFC data attached to the mesh.

I will report here as soon as the first test library is done, hopefully Friday

B by bitacovir on 25 Aug 2021 # +1 votes

@Coen said:

The tool from DWG to DXF I used make is ODA file converter

Are you using the 60 days Free Trial?

If you do and the free trial stops after the 60 days. You could use LibreCAD. The experimental DWG import works fine for these files.

Also, you can install nanoCAD 5.0 It is a freeware software.

C by Coen on 25 Aug 2021, edited 25 Aug 2021 #

@bitacovir

Are you using the 60 days Free Trial?

No, I don't think so. Atleast I have seen no mention of a trial period, seems like some batch tool.

You could use LibreCAD. The experimental DWG import works fine for these files.

Thanks for the tip. :-)

B by bernd on 27 Aug 2021 # +4 votes

@Jesusbill said:

@bernd I have done some work on the I beams, have a look at these commits

What I did was:

Export into csv files all the tables of the selected collections in the "data/profile_i" folder

Validate existing input values compared to data from another source. From these I identified some small differences shown in the first commits

Enrich the csv files with extra column properties

But when I update the blt/yaml file and attempt to write it back I get something much more ugly compared to the existing document and all the comments are lost, is there a specific way you prepare this file?

I have not forgotten about this ... There has been a lot going in FreeCAD FEM and in FreeCAD officials. But much more time consuming is our new earth dweller. It`s a boy :-) Thus less sleep and much less time for development ...

B by bernd on 27 Aug 2021 # +1 votes

I really like the possibility of exporting csv data.

You added the data as csv to the repo as well. Thus the data is duplicated. This is some risk IMHO. Should we not have one place in the repo where the data is saved? All existing YAML have been created manually AFAIK. May be we could add something to be able to convert the csv data into the yaml data?

BTW: Before I came to BOLTS I did not know YAML either. Since than I use it everywhere in favour of xml, csv and whatever. Since it is so easy to read and write by Python and can be edited.

L by lukas on 28 Aug 2021, edited 28 Aug 2021 #

Gratuliere zum open-source Nachwuchs :-) Besonders die Mutti :-), wie schafft Sie das zwischen Windeln und Tastaturen.

C by Coen on 28 Aug 2021 #

@Jesusbill

I will report here as soon as the first test library is done, hopefully Friday

Curious if you already found the time to show us a little part of the test library :-)

J by Jesusbill on 28 Aug 2021 #

@bernd great to hear from you, congrats about the baby boy!

I will respond to you as soon as I have time as I will be probably away from keyboard for the next two days.

In general I agree with what you wrote, no need to duplicate data, I just pushed the csv tables to show what I did and then we can figure out the best way. Sorry I don't have time now to write more.

J by Jesusbill on 28 Aug 2021 # +1 votes

@Coen I did found sometime this morning but it is a very much work in progress and I have mixed up things a bit.

I attach the ifc library file I created based on the HEA sections and I also created a short screencast in Blender.

Bear in mind that right now we have a profile panel in the scene properties where you can see the profiles that you import from the project library but there is no way yet to assign this to a structural member. But you can see the properties and the mechanical property set (this latter is shown only for the first profile so this is a bug to fix and we also need to indicate units; the pset is in mm, while the profile properties were converted to meters before creating the project library).

For this reason I also created IfcBeam and IfcColumn Types so that one can visualize the profile and even modify it from the object materialprofile panel, but eventually I think there will be no need for these Types if one is interested only in the profiles.

This coming week I will continue working on this (after Monday) and with @Moult I think we can take care of things needed like being able to assign from the list of profiles to an element without need of Type, take care of units, make sure we can visualize sections of all type etc.

J by Jesusbill on 28 Aug 2021 # +1 votes

sorry just realized I was not recording my mouse ...

https://www.dropbox.com/s/z8dekr11cgutj87/project_profile_library_demo.mkv?dl=0

C by Coen on 28 Aug 2021 #

@Jesusbill

That is absolutely awesome!!!