Newbie FreeCad "Pad" question

[Jim01]

Hey Guys,

So Santa bought me a 3D Printer for christmas, so I'm now at the stage where I'm trying to get my head around freecad, designing my first organisational object.

The below shape is the front of my object that I wish to pad into a 3D Dimension, it obviously isn't connected and needs to be a rectangle to be able to pad it, once it's rectangular and padded, how to I hollow it out so it resembles the shape I'm after?

Cheer's everyone!

[Geit]

You are right. Padding and pocketing only works with proper shapes. The easiest way to get your mind set-up for CAD is to think about paper.

If you do, you know that cutting out the line to get a proper 3D object is not working. The line is infinite thin. If you want to create a rail type thing (this is what I assume the shape represents), you need to draw a second line around. Connect a line to one of the small ends, go up the thickness of the object you want. Then in the same distance around the lines you made. That way the shape you created is no longer a line, but a real 2D shape with a width you could cut out of paper.

Thats the object you want to extrude:

[Jim01]

You are right. Padding and pocketing only works with proper shapes. The easiest way to get your mind set-up for CAD is to think about paper.

If you do, you know that cutting out the line to get a proper 3D object is not working. The line is infinite thin. If you want to create a rail type thing (this is what I assume the shape represents), you need to draw a second line around. Connect a line to one of the small ends, go up the thickness of the object you want. Then in the same distance around the lines you made. That way the shape you created is no longer a line, but a real 2D shape with a width you could cut out of paper.

Thats the object you want to extrude:

BOOM BABY!

Thanks Geit, I'll get onto it now!

[Jim01]

Is there an easy way to obtain 4mm borders all the way round? Or do I have to get the calculator out?

[Geit]

Not really, but check the last option in the draw icon section. A red square hovering over a blue dotted square.

Make sure nothing is selected before activating it.

Now all your drawing tools turn blue. Those are helper lines which are not part of the model, but help setting up dimensions. Draw a vertical line between the bottom and the inner bottom line. Now select the new blue line and one of the white small vertical ones on the top, which define the thickness of the wall.

Select "=" from constrains panel, to make the blue line equal to the white one and tada the spacing between the bottom lines is the same as the top ones. Same of course works for the vertical walls. Just draw a horizontal line between them and equal it with one of the other lines.

Use the square button again to return to normal draw mode with white lines.

If you select one or more lines and use this button, you swap the lines between white and blue, which is handy sometimes and faster than deleting and redrawing a line on the same position, but even so sometimes gets annoying, when you have e.g. a dot selected and want to switch line types, which creates an error message. Thats why it is important to ensure nothing is selected, before using the button.

[Jim01]

Nevermind I used the calculator to get a perfect 4mm border.

Now my issue is whenever I go to Pad, my work disappears!

There's also 2 random dots I can't seem to remove.

[Geit]

Instead of using the same measurement over and over, you should constrain them using the "=" constrain. That way you have only a few measurements to change and will not run into trouble and make the sketch more readable. See the image I posted above.

You can also give the lines names and let FreeCAD do the math, by just specifying the formula e.g. "width-2*wallsize". It is a little more work, but it is worth it.

Make sure a sketch gets green and is fully constrained. This is not a requirement, but avoids trouble and is the right way to do, especially when you want to change measurements later on, you must fully constrain all sketches or you part will "explode".

The "undeletable" dots are probably a line with a very short length. Lines can only be deleted when clicking on the line itself and not the dots. You can use the mouse wheel to zoom in until you can select the line, or draw a rectangular selection around both dots and then hit the "del"-key.

This line is probably the problem you have with extrusion. FreeCAD tends to draw nothing, when something impossible is required. Remember: The line is infinite thin and you therefor cannot cut a 2d line.

[Jim01]

You can also give the lines names and let FreeCAD do the math, by just specifying the formula e.g. "width-2*wallsize". It is a little more work, but it is worth it.

I just noticed that! a bit like naming your layers in photoshop, definitely will help for later on!

And you where right, is was a pesky line screwing it up!

Now how do I move the piece up the z axis so the new bottom is now in line with the base of the Y/X axis? I did a google and couldn't find anything

[Geit]

Well, you usually design a part the way you want to print it. You usually constrain the body to the center of the coordinate system, which is required to make it fully constrained (green).

However, if you modelled on the wrong plane, you can fix this the painful way. Click on body. In the data section below an entry "placement" should be visible. Now if you move your mouse pointer over the end of that data field, as little button appears, which opens a window, where you can change the position of your entire body in 3D space.

There is also right click on body and transform, but I find that is less accurate and even more confusing.

It is also possible to move the sketch onto another plane. e.g. x/Y. You just select the plane you want from body origin (not the global one) and use the "map sketch to surface" (it is next to the new sketch icon in part design, sketch symbol on the side of a blue cube). Click ok on the requester and done. This however can ruin your model depending on your design and references, so just be warned. It is better to work out the proper orientation before starting to design.

[Jim01]

Well, you usually design a part the way you want to print it. You usually constrain the body to the center of the coordinate system, which is required to make it fully constrained (green).

However, if you modelled on the wrong plane, you can fix this the painful way. Click on body. In the data section below an entry "placement" should be visible. Now if you move your mouse pointer over the end of that data field, as little button appears, which opens a window, where you can change the position of your entire body in 3D space.

There is also right click on body and transform, but I find that is less accurate and even more confusing.

It is also possible to move the sketch onto another plane. e.g. x/Y. You just select the plane you want from body origin (not the global one) and use the "map sketch to surface" (it is next to the new sketch icon in part design, sketch symbol on the side of a blue cube). Click ok on the requester and done. This however can ruin your model depending on your design and references, so just be warned. It is better to work out the proper orientation before starting to design.

Cheer's Mate! I moved it up, but it took the blue axis line with it, the project still exported out and onto cura correctly though, I've got it printing out now as I type as a prototype before moving forward with it.

This freeCAD is like learning Japanese... I've had enough brain bashing for 1 day/evening!

Next challenge will be adding countersunk drill holes!

[Geit]

Ah, thats what you wanted.

Cura will load the file in any position. It does not matter which orientation you design it. The only side effect is that it may be upside down or so, but there is a function in cura to rotate, so no need go think about that, when doing CAD.

The blue lines you refer to, are the axis within the object. You changed the origin of the body. Inside a body you design relative to the body. So you can move the body with everything else stays in place.

A simple way is to select the left dot of the bottom line, the right dot of the bottom line and at last the center dot. You may need to hold CTRL to select them together. Make sure you select the center dot at last. Now choose "><" from contrains panel. It will center the points around the point, which is also the axis.

This of course moved the entire object to center it. You could have just selected the left dot of your bottom line and then the 1/4 circle line with the Dot on the arc (second in constrain panel by default). You sketch should hop onto the line, unless you have some other constrain fixating it. This constrain ensures a dot and a line stay connected.

The first solution removes two grades of freedom, while the latter deals with just one as the dot is fixed to the axis, but the entire object is still able to move in x direction.

[Jim01]

Ah, thats what you wanted.

Cura will load the file in any position. It does not matter which orientation you design it. The only side effect is that it may be upside down or so, but there is a function in cura to rotate, so no need go think about that, when doing CAD.

The blue lines you refer to, are the axis within the object. You changed the origin of the body. Inside a body you design relative to the body. So you can move the body with everything else stays in place.

A simple way is to select the left dot of the bottom line, the right dot of the bottom line and at last the center dot. You may need to hold CTRL to select them together. Make sure you select the center dot at last. Now choose "><" from contrains panel. It will center the points around the point, which is also the axis.

This of course moved the entire object to center it. You could have just selected the left dot of your bottom line and then the 1/4 circle line with the Dot on the arc (second in constrain panel by default). You sketch should hop onto the line, unless you have some other constrain fixating it. This constrain ensures a dot and a line stay connected.

The first solution removes two grades of freedom, while the latter deals with just one as the dot is fixed to the axis, but the entire object is still able to move in x direction.

Thank you mate, this will be a massive help for next time!