Bibliotheca Alexandrina - making 2D drawings with FC

[F_Rosa]

To better understand the issue of producing 2D drawings with FC, I decided to transfer to CAD something relevant, like the architect Paulo Mendes da Rocha proposal by for the International Competition for the Library of Alexandria held in 1988. I have had a set of blueprints of the proposal because I have had the great opportunity to be part of the work team.

Again, the idea is to see how far we can go with current FC resources for the task of generating 2D CAD drawings for export and/or final printing. For this I basically used version 0.19, but I've also been checking the features of the current version 0.20.

I share with you some observations on the way I handled the matter to spread them, receive comments and improve them.

[F_Rosa]

If you are preparing drawings for DXF or DWG export, it is good to create and adjust the necessary layers for the 2D drawings in advance, this will avoid reorganizing the general structure of the file groups to incorporate them. Predict the set of layers for each drawing that will be needed (plans, sections, elevations, etc.), whether for exporting and/or printing (drawing sheets) using the Layer Management of the BIM Workbench. Then create folders (groups) according to the visualization and work organization of 2D drawings or 3D modeling. Insert the corresponding layers into folders (groups).

There are basically three basic ways to create 2D drawings in FC, although it is common to use a combination of them in the same drawing:

1. Making 2D drawings “from scratch” with the tools of the Draft, Sketcher (heavier) or Arch Workbenches, according to the desired layers.

2. Applying Draft_Shape2DView Projections. From the previous workbenches, create 2D and/or 3D drawings, positioning the 3D views in Top (for plans), Front, Right, Back or Left (for sections and elevations) and even Isometric (for isometrics). Select the desired elements and click on Draft_Shape2DView. If necessary, create or edit 2D drawings from a Shape2DView base.

3. Applying Arch_SectionPlane Projections. From the workbenches mentioned, create 2D and/or 3D drawings, positioning the 3D views in Top (for plans), Front, Right, Back or Left (for sections and elevations) and even Isometric (for isometrics). Select the desired elements and click on the section plane (Arch_SectionPlane). Adjust the positions of the section planes in the 3D drawing to match the desired plans, sections or elevations. Generate 2D projections of each cutting plane by clicking on Draft_Shape2DView. If necessary, create or edit 2D drawings from a generated Shape2DView base (by exploding it or drawing on it). This mode is very similar to the previous one, but it has the advantage of being able to modify the properties of the cutting plane, or even create new planes from an already created one, with the automatic updating of their respective projections.

[F_Rosa]

2. Generating the final drawing boards (TechDraw Workbench):

When working with the TechDraw Workbench it is good to activate the "Skip recomputes" option. Another measure to reduce the recalculation time is to preset the scale of the drawings in the TechDraw Workbench preferences (Scale tab, View Custom scale), in this way the inserted drawings will already be adjusted to the desired scale. Create a drawing sheet in the required format (A0, A1, A2, etc.), insert the desired views from the elaborate 2D drawings, 2D projections (Shape2DViews) or Arch_SectionPlanes, select them and adopt one or more of the available options:

1. DraftViews: Click on Insert Draft Workbench Object, generating DraftViews, adjusting the scales and positions. Insert captions, texts, images, margins and stamps.
• Advantages: it is lighter, colorized areas, subtitles and texts are maintained.
• Disadvantages: Elements are inserted individually. It is not yet possible to insert dimensions or fills of the elements (hatches), they must be implemented in the 2D/3D drawings on the 3D views. Multi-line annotations are not maintained, to correct this it is necessary to set the line spacing to a value close to the font size in the properties window.

2. Views: Click on Insert View, generating Views, adjusting scales and positions. Insert captions, texts, images, margins and stamps.
• Advantages: Elements are inserted together. It is the most complete option, in which it is possible to insert dimensions, hatches of the materials and modify the thickness, colors and types of a desired line. It is also possible to insert and remove elements from the set a posteriori, through the Source item in the properties window. You can select groups with layers.
• Disadvantages: tends to be heavier. Areas previously colored in the 3D views must be refilled (by solid hatches at the drawing scale). Annotations and titles are not inserted, for this, you must use the previous option (for some reason the texts inserted in this way “disappear” when we zoom in on the sheet) or use the tools of the bench itself. The lines must be adjusted again (color, thickness and type), that is, a general rework of the drawings is necessary. Be careful with the message “Can’t make faces from projected edges”, you must look for which elements are causing the problem, otherwise is not possible to select faces for inserting hatches, for example, avoid overlapping lines. If you still can't select a particular face because it's too narrow, decrease Edge Fuzz in the Advanced tab in TechDraw preferences and enable Use Polygon Approximation in the HLR tab in case you select lines that are too close or overlapping.

3. ArchViews: Create and adjust the Arch Workbench Section Planes in the 3D view and click on Insert Arch Workbench Object, generating ArchViews, adjusting the scales and positions. Insert captions, texts, images, margins and stamps.
• Advantages: Elements are inserted together. Information such as color areas and annotations are maintained. Automatically creates two line thicknesses (sections and views). It is also possible to insert and remove elements from the set a posteriori, through the Source item in the properties window. It is possible to complement the drawings with element fills and annotations coming from 3D, using Option 1, for this, create corresponding Shape2DViews projections and include them in the content of an Arch Workbench Section Plane (figures 7 and 8 of Vila Matilde House - https://forum.freecadweb.org/viewtopic.php?f=23&t=59192). If you only want to add some annotations of the 3D view, you can select the legends and click on Insert Draft Workbench Object (creating a DraftViews) and increase the line spacing to a size close to the font.
• Disadvantages: It is not yet possible to insert dimensions and hatches (they must come from 3D views) or edit the characteristics of the lines individually. The settings of the annotations fonts are unified, and it is not possible to individually modify their characteristics. It does not support objects inserted in layers, in this case you must select the elements directly.

[F_Rosa]

3. Exporting 2D drawings. In this case, there are two ways:

• From 3D views: Suitable for exporting files to other CAD programs as it retains the created layers. To do this, select the folder or group containing the previously created layers and export them to DXF or DWG. However, it is still not exporting the hatches. Exporting architectural drawings to SVG from 3D views creates huge drawings by working in meters rather than millimeters (the base unit of FC).

• From TechDraw Workbench: Suitable for exporting to PDF for viewing and printing or SVG for editing, however the files will be a single layer. If you want to export the final drawing of the drawing sheet in DXF, keep in mind that the created layers will not be kept, they will be altered according to the views inserted in the TechDraw Workbench, in addition the texts and hatches (whether they are bitmap or SVG) will not be exported ether.

4. Conclusions

For architectural/building drawings, the ideal would be to use the tools of the corresponding Workbench (Arch), leaving the 3D and/or 2D drawings practically ready and apply them on the TechDraw Workbench for export and/or final printing, but being able to modify, add and modify lines, hatches and dimensions in a free and diversified way, avoiding reworks and automating the modifications made in the 3D views.

Regarding the final drawing sheets, perhaps it would be important to further improve their exportation to CAD and/or SVG formats, as it would expand the possibility of using the resources of specialized 2D CAD or SVG programs.

Once again, I hope you liked it and this helps the work of spreading and improving FC.

[paullee]

The works is really professional ! as you always produced and showed previously

Can share a model template for reference and study please ?

Thanks

[ragohix769]

Just AMAZING, thanks a lot for sharing these tips and ideas, really appreciated

[Kunda1]

Holy smokes, this is friggin' amazing!

[F_Rosa]

Thank you for the feedback!

Paullee, regarding the model, for now I don't see clearly how, as there are many existing ways of performing the task of producing drawings. If I come up with an idea, I'll post again, ok?

[paullee]

Fair enough, look forward to your sharing of further projects and images

[eccioloste]

Waw. this is beautiful work!!!
Thanks for your detailed explanations, they will be very useful!