Problems with Pad when constructing girder bridge deck

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PeterSD
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Re: Problems with Pad when constructing girder bridge deck

Post by PeterSD »

I have now moved on to adding the fasteners to the Wall Frame as the next step,
I am doing this on your last file 'Deck.Rev 5.2 SHARM and using 'GirderRev.0_SHALM Fittings Template' as a reference (attached below).
I have a few issues when constructing Sketch007.
1. I could not remove the 3D Model using the method - Space Bar in the Model section. It stubbornly stayed visible. 3D Model The best I could do was to press the Section/Full View icon which replaced the 3D model with an infilled outline of the model which unfortunately has a dark infill !
2. Despite the above, I managed to select the two LH faces of the frame. The outer frame edge stopped short as it seems to have been interrupted by the Side Rib. I extended the line down to the correct length by using the inside edge of the Side Frame.
3. When I tried to add the two dots at the top and bottom of the frame and make these Symmetric it refused to do this. I then added 2 construction lines to the sketch connecting the top and bottom corners, added the dots and was able to set them Symmetrically.
Preparing Fastener Positions.PNG
Preparing Fastener Positions.PNG (133.34 KiB) Viewed 1132 times
4. I tried to add the dimension between the two dots above which resulted in the correct dimension given (21.5mm). Pressing OK resulted in the constraint error
Preparing Fastener Positions Dimension Constraint Failed.PNG
Preparing Fastener Positions Dimension Constraint Failed.PNG (91.97 KiB) Viewed 1132 times
Obviously The sketch could not be saved and therefore your file remains unchanged.
Kind Regards
Peter

Sorry, forgot to upload the reference file
GirderRev_0_SHALM_Fittings_Template.FCStd
(243.38 KiB) Downloaded 11 times
Last edited by PeterSD on Wed Jan 26, 2022 7:18 pm, edited 1 time in total.
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Shalmeneser
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Re: Problems with Pad when constructing girder bridge deck

Post by Shalmeneser »

My brain is down. MWE ?
PeterSD
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Re: Problems with Pad when constructing girder bridge deck

Post by PeterSD »

Shalmeneser wrote: Wed Jan 26, 2022 6:55 pm My brain is down. MWE ?
Thanks for your reply. No Probs.
Kind Regards
Peter
PeterSD
Posts: 167
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Location: UK

Re: Problems with Pad when constructing girder bridge deck

Post by PeterSD »

I have tried again with the Sketch. Previously, I had several files loaded into FreeCAd at the same time due to me needing to work with 2 files at the same time. Both files were tabbed at the bottom of the screen and I could switch between them by tabbing.I have now got a second computer working with FreeCAD and now I have one instance of FreeCAD on each computer. This change has allowed me to turn off the 3D model to give me a clear screen for sketching :D .
I then wanted to see if this has made any difference to the result of the dimension failure (21.5 mm between Symmetric dots in the sketch). BTW I was able to create the symmetry of the dots w/o using construction lines across the corners - another change from before.
Preparing Fastener Positions Second attempt.PNG
Preparing Fastener Positions Second attempt.PNG (27.68 KiB) Viewed 1021 times
Unfortunately, this failed and I believe this could be that I had to use 2 vertical lines on the LHS due to not being able to pick up the full length of the line from the body.
I think that it is worth removing the Wall ends (Sketch006) and trying this again. Any comments would be welcome. See Sketch007 for the above
Deck Rev 5 ,2a_SHALM.FCStd
(241.82 KiB) Downloaded 11 times
PeterSD
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Re: Problems with Pad when constructing girder bridge deck

Post by PeterSD »

I have deleted Sketch006 & Mirror. to remove the wall end ribs and created a new sketch for the fixings Drawing made and now only have the 2 parallel lines from the frame edges and the 2 centred dots. I still get a failure re Constraint2 when setting the vertical distance between the dots.
Well that rules out my hope.
I would welcome any thoughts.
UPDATE
See image below, the Solver message changed as I measured the distance.
Preparing Fastener Positions 2nd attempt.PNG
Preparing Fastener Positions 2nd attempt.PNG (107.66 KiB) Viewed 970 times
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Shalmeneser
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Re: Problems with Pad when constructing girder bridge deck

Post by Shalmeneser »

Your sketch is fully constrained BEFORE this try of last dimension.
So with this dimension, the sketch becomes over-constrained.

You want to fix this dimension (impossible) or to know this dimension (Sketcher_ToggleDrivingConstraint) ?
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Capture du 2022-01-27 18-50-41.png
Capture du 2022-01-27 18-50-41.png (4.67 KiB) Viewed 950 times
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Shalmeneser
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Re: Problems with Pad when constructing girder bridge deck

Post by Shalmeneser »

DatumLine upon axis ???
chrisb
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Re: Problems with Pad when constructing girder bridge deck

Post by chrisb »

PeterSD wrote: Thu Jan 27, 2022 4:10 pm I still get a failure re Constraint2 when setting the vertical distance between the dots.
A line can be completely described by the position of its endpoints. In your example both of these endpoints are already fixed (to be in the middle of the outer symmetry points). Any additional (driving=red) constraint makes it overconstraint.
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PeterSD
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Re: Problems with Pad when constructing girder bridge deck

Post by PeterSD »

Shalmeneser wrote: Thu Jan 27, 2022 5:50 pm Your sketch is fully constrained BEFORE this try of last dimension.
So with this dimension, the sketch becomes over-constrained.

You want to fix this dimension (impossible) or to know this dimension (Sketcher_ToggleDrivingConstraint) ?
Thanks for this. Read the topic and it gives me the way to create a named reference dimension which would be all that I need. What I shall do is to return to your file (and delete this file) and add this sketch. I was concerned that I could not get a single line from the outer edge of the frame unless I included the inner edge of the outer wall end.
Shalmeneser wrote: Thu Jan 27, 2022 5:56 pm DatumLine upon axis ???
I am coming back to your last file which includes a Datum Line. I have not yet gone into the detail but it was the next thing for me to work out,
chrisb wrote: Thu Jan 27, 2022 6:07 pm
PeterSD wrote: Thu Jan 27, 2022 4:10 pm I still get a failure re Constraint2 when setting the vertical distance between the dots.
A line can be completely described by the position of its endpoints. In your example both of these endpoints are already fixed (to be in the middle of the outer symmetry points). Any additional (driving=red) constraint makes it overconstraint.


Thanks Chris. I now understand this and it is the reason for my last image. I knew the sketch had become over - constrained and also knew that the dimension was required. A Conundrum which Shalmer helped me to overcome.
Kind Regards to you both
Peter
PeterSD
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Joined: Sat Nov 13, 2021 8:54 pm
Location: UK

Re: Problems with Pad when constructing girder bridge deck

Post by PeterSD »

Shalmeneser wrote: Thu Jan 27, 2022 5:56 pm DatumLine upon axis ???
I am back to your file. Regarding the DatumLine, your sketch (Labelled Wall Panel Frame) that I copied has an extra line below the sketch which is symmetric about the X axis and hence the frame. Is this the DatumLine you refer to as Object's X in the DatumLine function?
Deck Rev 5 ,2_SHALM.FCStd
(238.68 KiB) Downloaded 14 times
Kind Regards
Peter
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