FreeCAD 0.19 - Datum Plane

hello and welcome to another tutorial with me andrew today i'm going to be showing you how to use the datum plane within the parts line workbench you'll also notice that my freecad has changed slightly and that's because i'm using real thunders modback which is a few variations compared to normal if you'd like to know more about real thunder's mod i'll leave a link in the description down below so to start things off we're in the part-sign workbench and the datum icon is up here on our tool ribbon now mine might be in a slightly different location compared to yours as i've made the icons bigger it's pushed everything around a bit so this is what the icon looks like so i'm going to create myself a body as we need an active body to create a datum i'm going to make the origin visible in this mod i can tick and untick the eye but in older versions i can simply click on the origin and press the spacebar if i'm selecting any of the planes i'm going to click on our datum tool you'll see a yellow square appear along with some parameters to the left of our screen we have our references our attachment mode and our offsets now you'll see here it says not attached and below that it says selecting at this current point our modes don't work and our offsets are currently grayed out so this wants us to select our first reference for where we would like our datum plane to be so i'm going to select our x y origin you'll notice immediately how it tells us attached with mode plane face and our mode box has shortened in selectable options and we can now change some of these offsets you'll also notice that if i change our mode here that one of these is in bold this is the selection that freecad recommends based on the references you've selected there's a wiki page that i will link in the description below which goes into some detail about part attachment and the attachment mode then on the offsets we can move in all three axis as well as being able to rotate our plane and again manipulate it to how we want flip sides reverses our offset around the x y plane so if i was to put five in the z plane you'll see it move up and if i click on the flip sides you'll see how it has now been reversed on the xy plane you'll also notice in these boxes there is a formula icon which i'll come to a little bit later in the video moving on to our next example you'll see that i've got myself a cube here and what i'm going to do is i'm going to select the top face and i'm going to click on the datum plane now you'll see that the face that i selected has already been put into reference 1 and you can see that it's saying selecting now if i was to select another face like so you'll see that the reference doesn't move to the next box and it will continue to say selecting so i can select lines i can select vertices and i can select faces it's only when i click on reference 2 they will actually change and that will say selecting so again if i want this in the middle of this cube i can select the opposite face like so i can also start the datum tool without clicking any of these faces lines or vertices on the cube i can just click on the datum plane it will then ask me to select a reference so if i select this top face it will then move onto the second so the selecting and i can then click on the bottom face like so and it will move again onto selecting that's a slight difference to when you're just selecting a simple face but obviously if you're only selecting one face and then pressing ok then that's absolutely fine i can also select all the references before i click on the datum plane so again the same example if i want a date and plane between these two faces i've now selected those faces if i click on the datum plane you see how it's used those references and it's created a datum plane in the middle of our cube for this next part i'm going to move over very briefly to the main freecad program so some of you may know what i'm talking about when i say topological naming problem and what that is for those of you who don't know quoted directly from the freecad wiki it refers to the issue of a shape changing its internal name after a modeling operation such as a pad cut union chamfer or fill it is performed as an example of this you'll see here i've got myself three padded sketches one on top of the other not using any datums just simply clicking onto a face and creating a new sketch what i'm going to do is change our second pad sketch and see how that affects the rest of our geometry so i'll click on our second sketch and i'm just going to move this left hand line off the edge of our first shape like so i'm then going to click close you'll notice immediately how a sketch has randomly appeared also our third pad operation in our model tree has an error link to it this is the topological naming problem at first i thought i could get around this by creating a datum on each face and then attach a sketch to that datum unfortunately that just yielded the same results the way we can get around this is by creating a datum plane at the origin but then linking the datum to a piece of geometry using the formulas tab i referenced earlier so what i've got here is got myself a sketch and i've padded it what i'm going to do is i'm going to make my origin visible as i want to attach the datum to the xy plane so i'm going to click on the xy pane click on our datum point and you'll see we can now edit these features at the bottom i'm going to click on the function key down here which is going to bring up a formula box and i'm going to type in here pad dot length now you'll notice it has to be in capital letters so if i just click on the length there it will change the pad to a capital as well so what that has done is that's given me the length of our original pad which is 20 mil so i'm going to say okay and i'm going to say okay to that now whenever i change uh the length of this pad or the height of this pad the datum will move with it so i'm going to do now is i'm going to click on this this plane and i'm going to create another sketch again i'm just going to create a very simple box close out of that and i'm going to pad that by 15 mil like so and i'm going to create another datum on the xy plane like so and i'm going to click on the formula box again this time i'm going to say pad dot length plus pad 0 0 1 dot length like so and what that is doing that is creating an overall length of both of our pads so i'm going to say okay to that and as you can see it is now attached to the top of our second pad i'm going to say okay and i'm going to hide our origin point because i no longer need that i'll then create a third sketch on top of that datum point and again it's just going to be a rough box like so and i'm going to pad that by 10 mil now if i go back to our second sketch which is this one here and i now manipulate that like i did in the previous example like so close out of that and you'll see how everything has stayed exactly the same and that is how we solve the naming problem i can edit all of these geometries if i just have those data dating points it's a little bit easier to see so let's say i want the second pad and i want to add in some simple lines so like this and i'm just going to cut out that line there and close that you'll see how again everything stays the same if i change our bottom sketch like so you see again how nothing has changed we have created ourselves a solid piece of geometry which is easy to manipulate and change previous pieces of geometry but you're probably thinking that's a little long-winded and kind of annoying why can't i just draw on a face like any other cad software well with real fenders mod you can it solves the naming problem and makes creating geometry quicker and with less hassle so moving back into real thunder's mod the naming problem is no longer an issue you can see here that i'm creating sketches on faces extruding them and then manipulating past features to see if it causes any issues all without using a datum plane our geometry is solid which makes creating really easy speeding up our process at the same time i've read a few posts that are saying this mod could be added into freecad so hopefully that is the case obviously some parameters still exist such as making sure any geometry you create is attached to the main body otherwise this will still throw up an error so now i've briefly covered the naming problem and how we can get around that what are the other things we can use the date and plane for well one option would be instead of creating a sketch and offsetting it on our model we can do this with a datum plane i'll create a datum on our yz plane and use the formula icon to offset it from our part which will then make it stable for any future changes so i'm going to go down here click on our formula and i'm going to say pad dot length minus 10 millimeters which is my unit of measure when using the formula feature within freecad make sure to put the unit of measure at the end within this mod it doesn't matter but other versions you'll get an error message that looks a lot like this i think it's just a good habit to get into and can just limit problems within the future so i'm going to say okay to that and as you can see it is now 10 millimeter off the end of our cylinder if i say okay and i update our cylinder length so let's say i want it to be 100ml and say okay you'll see that our datum is still off the end of our cylinder which i'm going to assume is about 10 millimeters in my opinion i find this method a lot cleaner and it makes me feel better that hopefully i'm creating a more stable part that can withstand multiple back and forth changes so what if i want to create a date in between a few different points well in this case i'll click on my datum point and let's say i want to create it between a couple of vertices so i'm going to click on those two there and then i'm going to add a third one here and you'll see that it has created a datum point or date and plane between those three points so i'm going to say okay to that i'm going to click on that datum plane click on the sketch icon and i'm just going to create myself a piece of simple geometry and extrude that up and say okay so as you can see that is created from our datum plane but if i was to change that datum so let's say in the z i want to go down and say okay you'll see how it updates like so you can see that obviously the datum is in a place that would unlikely be able to be created unless it was between these three vertices so what if i then update this cube so let's say i change the actual width of this cube so i'm going to put that to 20 mil and say okay and you'll see how the datum conforms still to the three vertices that i picked you can see how the cylinder still conforms to that so what about if i change the length so i'm going to change that to 50ml again you'll see that the datum plane is still connected to the three vertices and the cylinder is still within the cube so for another example i want to cut this piece of geometry in half so i've got this datum plane which is whereabouts i want it doesn't really matter for this and i want to cut it in half so i'm going to select my box select my datum plane and i'm going to click on this icon within real fenders mod and that will slice it in half and you'll see in the parameters box that we've got both of our pieces left that'll be all for today's tutorial and i'd just like to take this opportunity to say a massive thank you to all of you who have subscribed liked commented and given feedback on how i can improve these videos and make it easier to learn as i said in the past i've got some exciting projects that i really want to share both free care related workshop related and a mixture of the two but as with all things nothing ever goes the way you plan but i guess that's part of life's rich tapestry thank you so much for watching i really appreciate it if you liked the video give it a thumbs up and if you dislike the video give it a thumbs down and as always have an epic weekend and i'll see you in the next video

Channel: Andrew CAD

Views: 22,006

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Id: 8DCsPCwWT3o

Length: 12min 9sec (729 seconds)

Published: Sat Apr 03 2021