OK, I'm Stuck... Complete Newbie

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chrisb
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Joined: Tue Mar 17, 2015 9:14 am

Re: OK, I'm Stuck... Complete Newbie

Post by chrisb » Mon Mar 23, 2020 1:28 am

You are right. It's a left over from a different display mode of the tree (you still can activate it in the preferences) where you see all loaded files in the same tree.
dave_w
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Joined: Thu Mar 12, 2020 12:37 am

Re: OK, I'm Stuck... Complete Newbie

Post by dave_w » Mon Mar 23, 2020 5:34 pm

chrisb wrote:
Mon Mar 23, 2020 1:28 am
You are right. It's a left over from a different display mode of the tree (you still can activate it in the preferences) where you see all loaded files in the same tree.
Thanks (again!) Chris. The preference is not obvious to me. Where might I find it? In the meantime, I learned I can create 2 instances of FreeCAD and just alt-tab between them without having the problem.

Here's another question. I was playing with dimensions and created a datum plane. I wanted to pad the new plane but when I placed my shapes the locations within the body didn't make sense. The distances just don't add up. So I used the ruler to measure previous rectangles I had created in a sketch. Here is what it looks like:
Image
The 66 mm and 61 mm dimensions are right, but the distance on the sides of the inner rectangle (previously centered) should each be ((66 - 61) / 2) = 2.5. But not only are those 2 dimensions off by about 0.4 mm, when I try to place other shapes on a datum plane on the inner rectangle, they are offset by that 0.4 mm.

Might that have something to do with snap? I don't believe I have that on. Maybe I should try...

Thanks,

Dave
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freedman
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Location: Washington State, USA

Re: OK, I'm Stuck... Complete Newbie

Post by freedman » Mon Mar 23, 2020 6:17 pm

The way I work; I don't use those measuring tools in the 3D window, ever. I keep all my dimensions in my sketches and my placements, which means I know the size of everything because I modeled it, I don't need any visible rulers. I went thru the same thing when I started using CAD. If you start from a premiss that you want a box a certain size and you draw that box to scale, there is no need for a ruler on the screen. If your trying to measure the distance between a couple bodies then use a shapebinder or look into the Assembly workbenches. Granted, the rulers could be used for stuff but I have never found them to work (snap) well.
Last edited by freedman on Mon Mar 23, 2020 7:46 pm, edited 1 time in total.
dave_w
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Joined: Thu Mar 12, 2020 12:37 am

Re: OK, I'm Stuck... Complete Newbie

Post by dave_w » Mon Mar 23, 2020 6:48 pm

freedman wrote:
Mon Mar 23, 2020 6:17 pm
The way I work; I don't use those measuring tools in the 3D window, ever. I keep all my dimensions in my sketches and my placements, which means I know the size of everything because I modeled it, I don't need any visible rulers. I went thru the same thing when I started using CAD. If you start from a premiss that you want a box a certain size and you draw that box to scale, there is no need for a ruler on the screen. If your trying to measure the distance between a couple bodies then use a shapebinder or look into the Assembly workbenches. Granted, the rules could be used for stuff but I have never found them to work (snap) well.
Thanks freedman. That is exactly what I'm doing. I only rotated in 3D so the numbers would show, but the rulers were done on the plane. And I don't use rulers to design, I use the dimensions in the sketch. So my math must be off somewhere. I'll re-calculate everything.

Thanks again.

Dave
chrisb
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Re: OK, I'm Stuck... Complete Newbie

Post by chrisb » Mon Mar 23, 2020 7:00 pm

It looks indeed as if the 2.9 is measured at a certain angle. If you want to measure afterwards what you modeled, I rather recommend to use the measure tools in Part workbench.
dave_w
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Re: OK, I'm Stuck... Complete Newbie

Post by dave_w » Tue Mar 24, 2020 12:31 am

chrisb wrote:
Mon Mar 23, 2020 7:00 pm
It looks indeed as if the 2.9 is measured at a certain angle. If you want to measure afterwards what you modeled, I rather recommend to use the measure tools in Part workbench.
I'm not a FreeCAD expert, and I don't play one on PC... But the dimensions I showed were taken with the ruler while the plane was flat, not tilted at all at any angle in any plane. I just re-did this:

Create a body.

Sketch, then draw a rectangle, X1 = 66 mm, center in x plane.

Pad.

Create a datum plane on the top surface.

Sketch then draw a smaller rectangle centered in x plane (mine is 5 mm smaller than X1, or X2 = X1 - 5 = 61 mm).

Pad.

Create a datum plane on that top surface.

Sketch then draw a smaller rectangle in x plane (mine is 3mm smaller than X2, or X3 = X1 - 8 = 58 mm).

I then show the body and see all 3 rectangles on the top view with no angles on any plane.

Zoom in so the distances between the lines is very large, then use the ruler. Measuring between the X1 and X2 rectangles, I see 2.9x mm where it should be 2.5 mm. Measuring between the X2 and X3 rectangles, I see 1.5x mm which is correct.

In all other respects, it seems the dimensions of the part are correct. The only thing that is odd is the 2.9x mm measurement, even though the rectangle itself appears to be the correct dimension.

Dave
dave_w
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Re: OK, I'm Stuck... Complete Newbie

Post by dave_w » Tue Mar 24, 2020 12:41 am

Oh darn. It is a 3D thing. When I'm clicking in a 2D view, FreeCAD locates the points in 3D, which changes the lengths dramatically.

These are not the droids you are looking for.

Dave
chrisb
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Re: OK, I'm Stuck... Complete Newbie

Post by chrisb » Tue Mar 24, 2020 7:51 am

dave_w wrote:
Tue Mar 24, 2020 12:41 am
These are not the droids you are looking for.
:lol:
dave_w
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Joined: Thu Mar 12, 2020 12:37 am

Re: OK, I'm Stuck... Complete Newbie

Post by dave_w » Wed Mar 25, 2020 10:08 pm

Another noobie question. (Should I start a new thread?)

I have a box which is padded on a datum plane on the inside bottom of the box. I now want to put a hole through the pad, but I want to countersink the hole on the outside bottom of the box.

I've tried creating a datum plane on the surface of the pad, creating a sketch with a circle, then a through hole on that sketch. The countersink is on the inside of the box, not the outside. If I reverse the hole, then the hole disappears.

I've also tried selecting the bottom outside surface and doing a hole on that. About the same thing. I think I might have tried creating a datum plane on the outside bottom, and that didn't work either.

Hints?

THANKS!

Dave
chrisb
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Re: OK, I'm Stuck... Complete Newbie

Post by chrisb » Wed Mar 25, 2020 11:09 pm

I have a rough idea what you are talking about, but it would be clearer if you upload the model, and perhaps some images illustrating the issue.
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