Difficulties following Part Design Tutorial

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woodsman75
Posts: 6
Joined: Sun Feb 14, 2021 2:57 am

Difficulties following Part Design Tutorial

Postby woodsman75 » Sun Feb 14, 2021 5:16 am

Hi,
I love what I believe FreeCad could do, but unfortunately, I'm not an architect, or PE. I haven't even had a CAD class. Nonetheless, I'm wanting to use FreeCad at least initially for doing a simple printer stand out of wood. For an open source project, this is incredibly well documented. Still, some details are missing. I'm trying to follow this tutorial:

https://wiki.freecadweb.org/Creating_a_ ... PartDesign

I'm using Linux FC 30 with a MS mouse having a left and right button, and a scroll wheel that seems to act as a middle button.

I would request whoever writes the tutorials to say which specific button to click rather than saying just "click". Also, when I'm drawing a line, I learned you have to press Ctrl to get it to work, but that wasn't mentioned on this guide.

I'm having these problems that I request help with:
* My problem is that the grid keeps changing from 10mm to 4mm. Even worse, it keeps hiding all of the grid lines except for those near the lines that have already been drawn. This happens after the first line segment has been drawn. The problem is that it makes it hard to find the next point to plot.
* I got the 30 degree constraint added, but it extended the diagonal beyond the y axis to form an angle to work with.
* I wish I could just tell it the line length or type in the point coordinates. Dragging a line is hard to get right, especially when FreeCad hides the needed gridlines.
* If I need to move the point because I made a mistake, how can I move just one point on a line segment?
* I'd like to set that 50mm constraint along the X axis, but this is really more like a constraint put on a dashed/imaginary line.
* Separately, If I want to make a blueprint of a slice of the 3D diagram, what should I read more about?



Thank you for reading, and help on any one or all of the above. I've used the product enough to see it works really well once you know what you're doing.
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Grid being hidden
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chrisb
Posts: 33681
Joined: Tue Mar 17, 2015 9:14 am

Re: Difficulties following Part Design Tutorial

Postby chrisb » Sun Feb 14, 2021 6:41 am

You have probably edited in Sketcher the "Edit controls" and switched the "Snap to grid" on. This is not recommended, because it suggests that the points have been fixed, which they are not! The grid is only an editing aid, and you still have to use the constraints as described in the tutorial. I recommend even to switch the grid off.
Once you have finished the tutorial you may read about it in the sketcher lecture linked in my signature.
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
heda
Posts: 318
Joined: Sat Dec 12, 2015 5:49 pm

Re: Difficulties following Part Design Tutorial

Postby heda » Sun Feb 14, 2021 7:47 am

it looks like you have selected "open inventor" as mousemodel.
I think almost all documentation and tutorials are written with "CAD" as mousemodel.

Mouse_Model#OpenInventor_Navigation

personally it would drive me mad if I had to press ctrl for every time I have to select something.
I find the CAD mousemodel to have good usability.

for changing location of a point (or line for that matter), just select it (meaning click) and drag it to where you want it to be with the mouse button down.
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funkysod
Posts: 25
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Re: Difficulties following Part Design Tutorial

Postby funkysod » Sun Feb 14, 2021 8:59 am

I agree, you probably have a different navigation style selected. I find "gesture" or "touchpad" to be most intuitive but that's personal preference. And the grid can be confusing. My preferred method is to draw the first line, fully constrain it (or at least dimension it) to get a feel for size and proportion. Then I sketch the rest, approximating size and relations, then proceed to fully constrain it. This way you can disable the grid.

It may sound counter intuitive but with auto constrains on and avoid redundant auto constrains enabled and dimensioning the first most significant sketch element it's way faster than trying to use the grid as reference. At least that's my experience.
woodsman75
Posts: 6
Joined: Sun Feb 14, 2021 2:57 am

Re: Difficulties following Part Design Tutorial

Postby woodsman75 » Sun Feb 21, 2021 3:59 am

I thank anyone who takes the time to read and reply; you and everyone else was right about my setup (very impressive). However, I was not able to enable the line create tool without first switching to Sketcher. Also, I wanted to use the grid to do the part as close to the prescribed method as possible, and they got the tool to not hide the grid somehow.

Short of a grid, I'd like to be able to tell it to begin at a certain point and either specify a length or an end point. Having not been a CAD person before, maybe this is not the way people normally do it at this point though. I have been able to add the parallel, angle and length constraints though.
chrisb wrote:
Sun Feb 14, 2021 6:41 am
You have probably edited in Sketcher the "Edit controls" and switched the "Snap to grid" on. This is not recommended, because it suggests that the points have been fixed, which they are not! The grid is only an editing aid, and you still have to use the constraints as described in the tutorial. I recommend even to switch the grid off.
Once you have finished the tutorial you may read about it in the sketcher lecture linked in my signature.
chrisb
Posts: 33681
Joined: Tue Mar 17, 2015 9:14 am

Re: Difficulties following Part Design Tutorial

Postby chrisb » Sun Feb 21, 2021 7:05 am

I understand the desire for a grid and it can indeed be helpful for a first go, but after the initial layout you really should consider to switch it off. It detracts from sensible modeling with geometric constraints.

If you prefer to enter the points one by one by their coordinates, you may be better off with the Draft workbench.
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
woodsman75
Posts: 6
Joined: Sun Feb 14, 2021 2:57 am

Re: Difficulties following Part Design Tutorial

Postby woodsman75 » Sun Feb 21, 2021 7:16 am

I made progress, but now have this blue "XZ_Plane" square in the picture. I wish I could hide this out of the way. It says there's 2 degrees of freedom which I interpret to mean two places where the shape could be twisted, moved or otherwise distorted. I think it's because the line on the left is really 2 lines, one smaller one larger, but together they join. I had great difficulties getting that dialog that shows the lines, but eventually found it under elements. But I'm also color blind, red and green so it's a bit hard to tell and zooming in does not help, especially since the selected line is green, and the constraint is red.

I read the comments in this thread and wish I could apply them. I could not get the tool to allow me to draw a line segment without going into the Sketcher mode though others have mentioned not using that mode for this purpose. Also, there seems to be no obvious way to show the full grid. Earlier it seemed to show the grid only after a line or point was made, but this time it did not want to do that for me. Most of my progress was made by adding constraints rather than counting grid points. I respect that maybe people don't normally use grid points, but if the tutorial shows the grid, I'd like to do it like the example, it would make me feel more like I'm on the right track.

I'd like Freecad to, upon clicking on a line to bring up the relevant dialog for that line. What's making this immensely difficult is coming from drawing programs like InkSkape or sometimes Gimp.

https://imagebin.ca/v/5sUufTzgJaVI
chrisb
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Re: Difficulties following Part Design Tutorial

Postby chrisb » Sun Feb 21, 2021 9:07 am

woodsman75 wrote:
Sun Feb 21, 2021 7:16 am
I made progress, but now have this blue "XZ_Plane" square in the picture. I wish I could hide this out of the way.
This is from the body's origin. Select the origin and hit the space bar to hide it.
It says there's 2 degrees of freedom which I interpret to mean two places where the shape could be twisted, moved or otherwise distorted. I think it's because the line on the left is really 2 lines, one smaller one larger, but together they join. I had great difficulties getting that dialog that shows the lines, but eventually found it under elements.
I will look at this in a minute when I'm back at my computer.
But I'm also color blind
Configure the colors in Preferences->Sketcher->Colors.
I could not get the tool to allow me to draw a line segment without going into the Sketcher mode though others have mentioned not using that mode for this purpose.
That can only be misunderstanding. You have of course go into Sketcher to add lines (not talking about Draft here).
Also, there seems to be no obvious way to show the full grid.
You can rotate 3D view arbitrarily, which means the grid could go to infinity, which would take infinitely long to calculate. Thus the grid is limited.
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
chrisb
Posts: 33681
Joined: Tue Mar 17, 2015 9:14 am

Re: Difficulties following Part Design Tutorial

Postby chrisb » Sun Feb 21, 2021 9:17 am

chrisb wrote:
Sun Feb 21, 2021 9:07 am
It says there's 2 degrees of freedom ...
I will look at this in a minute when I'm back at my computer.
Please upload the model.
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
Brutha
Posts: 189
Joined: Mon May 04, 2015 1:50 pm

Re: Difficulties following Part Design Tutorial

Postby Brutha » Sun Feb 21, 2021 10:10 am

woodsman75 wrote:
Sun Feb 21, 2021 7:16 am
Most of my progress was made by adding constraints rather than counting grid points.
This is exactly the way it works in fact!

In most art or old CAD programs, you have to put the precision in at the beginning.

With sketching in FreeCAD it's exactly the other way round - you roughly draw the shape you want without worrying about it being accurate. Then use the constraints to add precision.