workflow for beginners

Hi,
Slightly embarrassed to ask here, but I did not find a beginners’ forum. I am totally confused. I did most of the Artigas tutorial about 18 months ago, but then had to stop for other things… Coming back, now on version 18, I am trying to model a building we are buying, but my workflow on Freecad must be faulty, and I cannot find a clear summary of good practice or of the way the operations in Freecad actually work.

My version:
OS: Debian GNU/Linux buster/sid
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.15221 (Git) AppImage
Build type: Release
Branch: master
Hash: fc5b6288c6eb4fe89192f63f1fbdf4a43c0fad27
Python version: 3.6.6
Qt version: 5.6.2
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: French/France (fr_FR)

As I understood it the workflow should be:

  • import the dxf
  • use Sketcher to copy a line representing one face of a wall.
    This entails anchoring the endpoints to lines on the base drawing, after activation external geometry.
  • switch to Arch workbench to generate the wall. Edit its data to suit.
  • highlight a face of a wall and switch back to Sketcher to draw the outline of an opening on the wall face.
  • switch to Part design in order to have access to “pad” and “pocket” tools, use pocket to cut the hole.
    This leads to having to create a “Body”. I do not understand the relationship between the body, the
    wall and the sketch. Sometimes it works.
  • repeat the above as needed. Join walls using Arch add, but better not to do so until all openings have
    been made, as drawing on the correct face of the correct wall becomes tricky.

I am ignoring the floor slabs in the above, as they seem slightly simpler to manage.
So my first question is "Is this the right sequence of work, or is there a simpler way?

And the second question is really a list of the main difficulties I have encountered. Some may be just the
result of the relatively early stage of development of Freecad, but some are likely my unfamiliarity with
this complex application:

1- The tree view becomes really confusing, and my attempts to rationalize it by grouping, say, walls under a
separate group results in many items being duplicated or linked to. I guess it must be important to place
the cursor at the bottom of the list before beginning any new item, to avoid things becoming children of
unrelated items.

But the worst problems I have found are:

2- Trying to cut a hole in a wall and getting this error:
" In order to use this feature it needs to belong to a part object in the document."
I do not understand what is a part object or which document is intended.

3- Trying to draw in Sketcher on a wall surface can be extremely difficult as the screen becomes covered
in a grey mist caused by Freecad trying to draw a 1cm grid, even if the grid is defined as 1m. Also,
the base drawing becomes invisible behind the base of the wall and any adjacent floor slabs, meaning
it is nearly impossible to snap to lines or points to create construction lines. There is also no indication
when construction mode or modem mode is active, so lines have to converted.

4- Sometimes, for no apparent reason, all the base drawing lines are non-snappable - the cursor shows a
no-parking sign.

5- Highlighting an item, a sketch for example in the project tree, sometimes causes it to appear highlighted
in the view, but sometimes not.

6- Constraints: It is not possible to identify which constraint says what. There can be five coincident
point constraints listed, but I cannot tell which one I need to delete to resolve a problem. Sometimes
they do not disappear when deleted.

TIA for any guidance.

The “Help on using FreeCAD” subforum is your one stop for everything. https://forum.freecadweb.org/viewforum.php?f=3

Often the moderators move the threads to here or other sections if they think it’s appropriate.

I am totally confused. I did most of the Artigas tutorial about 18 months ago, but then had to stop for other things… Coming back, now on version 18, I am trying to model a building we are buying, but my workflow on Freecad must be faulty, and I cannot find a clear summary of good practice or of the way the operations in Freecad actually work.

Not everybody knows what you are talking about. What is “Artigas tutorial”? Is it a webpage, a blog, a video? If you have the resource, you should post the link to it.

FreeCAD has developed pretty fast in the last 2 years. Version 0.17 introduced important changes with respect to 0.16, so you could say 0.16 became obsolete from one day to the next one. Not only that, many experienced users started using 0.18 immediately the day after 0.17 was released, as most changes are updated daily and are fairly stable. Now, 0.18 is finally officially released, but again the main developers and power users are going to be using the 0.19 development version from now on. My advice to you is to look for resources for the 0.17 and 0.18 versions, and don’t pay too much attention to resources that are older than that. In the FreeCAD timeline, information that is 18 months old may be too old. Some information from 0.16 is still valid, but many things that describe PartDesign have changed, so you should focus on 0.17 onwards.

As I understood it the workflow should be:

Workflow for what? Not everybody uses FreeCAD for the same objective. Some import DXFs, others just build their geometry from scratch. Importing DXF is helpful if you want to build an architectural plan. Is this your objective?

  • import the dxf
  • use Sketcher to copy a line representing one face of a wall.
    This entails anchoring the endpoints to lines on the base drawing, after activation external geometry.
  • switch to Arch workbench to generate the wall. Edit its data to suit.

The Arch Workbench works much better if you use base 2D geometry from the Draft Workbench, as Arch imports all tools from Draft, and basically works on top of it.

  • highlight a face of a wall and switch back to Sketcher to draw the outline of an opening on the wall face.
  • switch to Part design in order to have access to “pad” and “pocket” tools, use pocket to cut the hole.
    This leads to having to create a “Body”. I do not understand the relationship between the body, the
    wall and the sketch. Sometimes it works.
  • repeat the above as needed. Join walls using Arch add, but better not to do so until all openings have
    been made, as drawing on the correct face of the correct wall becomes tricky.

It is a bad idea to mix PartDesign Workbench objects with Arch Walls if you are a beginner and don’t know what you are doing. Stick to using Draft objects and Arch objects. You don’t have to use PartDesign Pocket to create openings in Walls; create a simple Part Box (from the Part Workbench), and subtract that if you must. If you use PartDesign, you must subtract an entire “Body” (PartDesign Body) from a Wall, not the individual features (Pad, Pocket, Fillet, etc.).

If your intention is to create Windows and Doors, Arch provides a more convenient mechanism, the Arch Window tool, which creates the appropriate Window or Door shape, and automatically makes a hole in your Wall for it.

1- The tree view becomes really confusing, and my attempts to rationalize it by grouping, say, walls under a
separate group results in many items being duplicated or linked to. I guess it must be important to place
the cursor at the bottom of the list before beginning any new item, to avoid things becoming children of
unrelated items.

There are some quirks with the way the Tree view works, and they may not be entirely intuitive. Creating Arch objects is usually very simple. Select a base object, for example, a Draft Wire, and then hit Arch Wall. The wall is created, and the wire is immediately placed “inside” the Wall. Then you can move the Wall inside a Group (Std Group); if you need to modify the Wall, modify the base wire, and refresh the model to see the changes.

However, the very same wire can also be used with another tool, for example, Arch Structure. This means that the same base shape can appear inside different objects and groups. Depending on the order in which you create the elements, these objects may appear messy in the tree view.

If you see too much clutter I suggest this, drag the elements to the root node in the tree, the one that with the name of the file, “Unnamed” by default. When you drag and drop an object there, it will often clean up some objects that appear inside others. Then you can move them to groups.

2- Trying to cut a hole in a wall and getting this error:
" In order to use this feature it needs to belong to a part object in the document."
I do not understand what is a part object or which document is intended.

Don’t mix PartDesign with Walls. It sounds like you are trying to use Pocket with a Wall. It won’t work. Pocket, Pad, Hole, etc., only work within the same “Body”. A Body is a single contiguous shape. For example, a gear is a solid “Body”; it can be built from a sketch, a pad, and then different holes, subtractions, and fillets. PartDesign is meant to build solid mechanical shapes like that, not architectural walls.

3- Trying to draw in Sketcher on a wall surface can be extremely difficult as the screen becomes covered
in a grey mist caused by Freecad trying to draw a 1cm grid, even if the grid is defined as 1m. Also,
the base drawing becomes invisible behind the base of the wall and any adjacent floor slabs, meaning
it is nearly impossible to snap to lines or points to create construction lines. There is also no indication
when construction mode or modem mode is active, so lines have to converted.

Don’t use the Sketcher Workbench with Walls. Use Draft with Arch. Arch already includes Draft, so use those tools. Draft includes the Draft Snap system which allows you to create grids and workplanes, co-planar with any existing Wall, so you can correctly constrain and position your wires.

Arch does use Sketches as the base shape of Arch Windows and Doors, but the usage is simple. Just click the Arch Window button instead of drawing the shape yourself.

4- Sometimes, for no apparent reason, all the base drawing lines are non-snappable - the cursor shows a
no-parking sign.

I don’t really understand this.

5- Highlighting an item, a sketch for example in the project tree, sometimes causes it to appear highlighted
in the view, but sometimes not.

Sketches will be visible if they are visible, and their Body is also visible.

6- Constraints: It is not possible to identify which constraint says what. There can be five coincident
point constraints listed, but I cannot tell which one I need to delete to resolve a problem. Sometimes
they do not disappear when deleted.

It’s difficult to tell what is going on here without an example or pictures.

Follow the tutorials. They are meant to introduce you to the best practices of creating architectural drawings.

  • Tutorial for open windows: I suggest this as a very basic introduction.
  • Manual:BIM modeling: another simple tutorial with fairly simple basic wires.
  • Arch tutorial: this long tutorial is the primary document that showcases the Arch workbench, making use of many of its tools. It is extensive, but may be too complex for beginners. It was made in FreeCAD 0.14, but it still works pretty much the same now, as the Arch and Draft tools haven’t changed much since. The only issue is that the Drawing Workbench to produce floor plans is no longer supported. You should use the TechDraw Workbench as described in the first two tutorials.

vocx: Thank you for your thorough and useful reply. With that and a few more days of work, I shall be well set up!

I spoke a little too soon. I have been following along the beginners’ tutorials on youtube,
in the series that starts https://www.youtube.com/watch?v=_HEvhclR4-o .
I have arrived at lesson 4 (https://www.youtube.com/watch?v=cRFsW_FhyP4). I am
aware these relate to an earlier version, but have made small adjustments such as not
needing to press ctl key to select multiple items, etc. When trying to rotate objects, I
notice a serious problem that I cannot explain.

For example in this video, after selecting the XZ plane for the drawing in part design and
preparing the drawing exactly as shown, the extrusion using the “pad” tool works correctly,
but the object created disappears from view. After zooming, I can find the object, but
cannot rotate it because there is a large grid plane about 3 x 10^6 mm away in the Y
direction. I thought at first that the created object must have somehow been moved away
from the origin, but it claims to be located at (0,0,0).

This is the most extreme case, but I noticed other strange displacements and
disembodied plane grids while I was running through other tutorials. Does the creation of
a part establish a local origin different from the global origin? If so can they be reunited?
The size of these huge planes of grid also leads to “zoom to fit” showing nothing but a
line and a dot on opposite sides of the screen. The line is the grid plane seen edge-on,
and the dot is the model being built.

What am I doing wrong?

If you have general PartDesign questions those are better handled in the Help Users subforum https://forum.freecadweb.org/viewforum.php?f=3 As most questions about general 3D modelling are quickly explained there. This subforum should be for specific questions about Arch, building modelling, IFC, BIM, etc.

Interestingly, the series of tutorials that you point to was made by Roland Frank who was an active contributor to FreeCAD and who sadly passed away in 2017. You can even read some threads from him in this forum, under the nickname of “r-frank”.

I thought at first that the created object must have somehow been moved away
from the origin, but it claims to be located at (0,0,0).

Does the creation of a part establish a local origin different from the global origin? If so can they be reunited?

Be very careful with your terminology. PartDesign works with a PartDesign Body (blue icon); however, version 0.17 introduced the concept of a Standard Part (Std Part, yellow icon), also called “App Part” by developers and power users, which can be used as a generic container to hold multiple Bodies and other things.

If you are a beginner, you should use PartDesign Bodies, and avoid Std Parts (App Parts). They both define a local coordinate system with which you can position your objects in the 3D space. Moreover, a Sketch also has a Placement property. So, if the Sketch is outside a Body, it will use the global coordinate system; and if it’s inside a Body, it uses coordinates relative to the Body’s origin. In this case, moving and rotating the sketch may not work, as it will depend on the placement of the Body. Moreover, it’s really hard to see what you mean if you don’t provide images or example files to explain your issue.

So, yes, you can set the Placement property of each object to [0,0,0] with 0 rotation, to have them in the origin. Then you can change the Placement values, recompute the model, and see the effects.

Why do Std Parts exist? Well, they are thought to be helpful in the future, as a core component of a future “Assembly Workbench”. For example, a Std Part may hold different PartDesign Bodies by means of assembly rules (contact, coincidence, concentric, etc.). Currently, if you want to create an assembly, you would probably have to create many Bodies, and manually edit their Placement property to put them where you want exactly.