FreeCad Tutorial : Datum Planes and Local Coordinate Systems

hello viewers welcome back to another freecad tutorial datum planes and local coordinate systems are essential building blocks in pre-cad modeling fully defined in the datum planes and local coordinate systems helps to avoid errors in parts and assemblies now what is meant by fully defining define datum planes or lcs xyz coordinates in definitive direction without any ambiguity there are several ways you could do this attaching to faces vertices and edges o and x o o x y attachment modes are not all that intuitive for a beginner and this tutorial will help in understanding these attachment methods so let's start by creating a new file so i'm going to create this new file which is called unnamed so you can go and give it you can give a name so i'm going to use a same body okay then inside this simple body i'm going to put a body then define a sketch so pick the x y plane and define that sketch uh i want to create a hexagon here and i'm not going to dimension this that's not important in this case then um pad this guy so this my simple body now you will notice that there is this origin okay what is this origin so origin is consists of x y z coordinates and the associated planes so i can switch on this origin by pressing the space bar key and you can see how this is you know defined now every body when you open up a body or create a body it will have its local origin and it if you translate this body it will move along with that okay so this is kind of a it's this origin is kind of stick to the body and it will always move and that the and then that's kind of intuitive because this body was based off of this origin and this x y coordinates because you have to define some units of size so that's why we have this origin and these coordinates okay now let's get to our subject where i want to create a datum plane so in this case i'm going to uh i'm going to keep it for for this origin on for now and if i just create this datum plane by clicking here it will always go to this default xy plane that way i created that sketch it will always go to that and then what you can do is this is more like the attachment menu where you can use these uh attachment features in this menu to attach that datum plane any way you like it now this one is more like the references that you define or you can say attachment locations and this is the attachment mode and these are the attachment offsets okay we're gonna play with all of them and see how we can get this plane wherever you want it so first thing i'm going to do is i'm going to pick uh some space on this body now when i pick this face this play and datum plane is going to attach to this and i can keep picking if i go back and start saying i'm selecting this and i pick this keep going you can keep moving that wherever you want to attach it now uh this is the simplest form of attaching the datum plane to a body phase now um this is the advantage is this is pretty easy the disadvantage is this plane has its own local coordinates and you don't know where those local coordinates are because you don't have a way to define that now you can go back and put it here let's see and now i put it in this face now i have to do a guess see where and how this x y z of this datum play a data plane is now if i go and play with this you know this offsets i can get an idea okay x in this this direction because when i increase the x direction plane size keeping keep increasing in these directions and local y would be perpendicular to that so it will expand in this direction right so that's simple way of defining a plane onto the body so i can say okay can get out of it and your plane is defined so i'm going to switch off this origin for now now there are better ways of defining the plane in the body so let's get rid of this plane and then start from sketch again this time i'm going to be a little bit more intelligent in defining this plane so what i'm going to do is let's say i want to have this datum plane aligned with this face with this actually with this face but i want to define my x in this direction in the vertical and y in the horizontal direction so how do i go and do that so first thing you can do is in the selecting pane you can pick this node okay now i want to have my i said i want to have my x in this direction so i'm going to pick this second point here or the vertex here and now it kind of moved it in between but that's all right we can change that so the way i want i'm going to do that is i'm going to instead of allowing it to use this inertia 2-3 which is essentially the uh the plane in between these two points uh or the the line forming these two points and you can it will use the line and then put a plane in between those two points perpendicular to that line so that's this inertia 2-3 but i don't want that i'm going to go along the align o x y now what it did was it created this plane along these two lines it is starting with this origin going in x direction and it needs to have a y direction so i can define the y direction let's say if i pick this node what it did was okay it put this plane uh in this plane now let's see where it's x y is so if i increase my x it is in this direction and if i increase my y it is in this direction so i achieved my original objective of defining the plane the directions i want you might ask why do we need this defined like simply the simple explanation is that when i go and create a sketch on this selecting this plane now my x is aligned in this direction y is aligned this direction so simply that's the reason uh and there could be many other reasons so there's another method you can define the plane uh to a body so let's get rid of these the items that i already created get rid of the sketch start with the template again this time around i'm going to uh define it let's say i'm going to pick another point vertex here and then i'm going to pick this second vertex let's say vertex here so um now it by default it puts it in between those two points that's not what i want so i'm going to go and say aligned o n x i'm going to pick this one let's see what happens if i do that now and then i'm going to select this point okay now this point i want to pick um [Music] something like this point now what it did was now if i define this what it really did was it put the plane in my first point which is kind of the origin of that datum plane so this point and this point and this one which is the two word these vertices form the normal of this plane so it is now aligned this plane is aligned normal to these uh the the line that is formed by these two uh vertices okay and then its x coordinate is this i put this third point so this x direction should be this direction the local coordinate of the datum plane x is aligned with this so we can check this by offsetting it see how it is growing so yes it is growing in the x direction and if you want to go and check it further you could do by picking a datum or a sketch and now your axis direction is in the in the height direction of this body so um as you learn now there are multiple ways of defining a plane using this attachment scheme so we call the plane parameters is essentially you by selecting you know your attachment locations on the references and the attachment mode and then you can also offset it next thing we want to do is to create a local coordinate system now one should not get confused the local coordinate system with the origin now the origin is essentially a coordinate system but it is not a local coordinate system okay so when you want to create a local coordinate system click on this and it will give you the same menu as earlier where you have the attachment locations or the references attachment mode and the attachment offset now what you can do here is you if you want to align this coordinate system to this location you can pick this vertex now it has essentially translated the origin of the coordinate system to this vertex which is the attachment mode as referenced here now the second one you want to do is to say pick a point any way you like it let's say i want to have a second one of the axis aligned in this direction so i pick this guy now what it does is it went and give you the inertial coordinate system if you want to stick with it you can stop here but one thing to keep in mind is that the coordinate system is not fully defined and if you don't have a fully defined coordinate system you're going to have a problems when you do like assemblies and animations you're going to have problems with that so we'll get to that in a separate tutorial but for now uh i don't want this inertial cs i want to go and pick one of these ones where let's say i want to have the z in this direction uh so i'm going to have to pick this one as the attachment mode which is o z x and the third point you have to pick is my x axis needs to be either in this direction or in this direction or any direction you want i'm going to pick this direction so i'm going to pick this vertex let's say it's not picking it up okay there you go so now you can see that it is my accents is in this direction so my coordinate system the local coordinate system is fully defined now if i close out and essentially but if you translate this body the local coordinate system will go along with that and you know you can do assemblies down the road now let's do a one more example in a different way now typically in this like a symmetric body like that like this one you want to put a coordinate system somewhere in the middle right so how do we do that so one method you can employ here is you can create a datum point now this datum point is created in the origin and what you can do is you can translate to the this uh the center of this hexagon so how do we do that is using these references so let's start with this pick this guy okay so now it worked okay so we are at the center of this hexagon i'm going to keep that point in that center now we can go and create the local coordinate system i'm going to pick the point i already created and now for the second reference since i want this z-axis in this direction this is already these as aligned with that but i'm let's say i'm going to pick this guy now i let's say i want to have my x-axis gala going along the center of this uh hexagonal prism all i have to do is go and pick this o x okay so x will be in this direction so i'm going to say ox now um i have the x axis going along this center of the the body and now i you can assign my x or z or y any direction i want since y is i already pick o x y so y can be assigned to any direction any of these six nodes so let's say i pick this guy now y is in direction z is the direction and x is going through the center my local coordinate system is fully defined uh so this is how you create your local coordinate system so this would be very useful when you go into doing assemblies and even when you do uh you know animations in assembly four uh this is going to be very useful so i'm going to create a another tutorial on that so um i hope you know this would kind of gives you a flavor of how you create local coordinate systems as well as datum planes and fully define them so that there is no guess work on the directions of the each coordinate system so this is a quick tutorial i hope you learned something new if you would like to subscribe please go ahead and click on the subscribe button and leave any comments thank you

Channel: CADZiS

Views: 803

Keywords: Freecad;, FreeCad, Constraints, Geometric Constraints, Sketcher, Modeling, 3D Modeling, 3D Printing, cell phone, Planes, sweeping, Draft, Drafting, draft workbench, datum line, datum plane, snap, draft creation tool, Model Tree, Tree View, Standard Part, Part Workbench, Part Design workbench, cumulative single solid, Carbon copy, cut and paste in freecad, shape binder, Subshapebinder, sub shape binder, O-N-X, O-X-Y, datum point, LCS, Local Coordinate system

Id: mMAznTZ1-7s

Length: 19min 5sec (1145 seconds)

Published: Fri Nov 05 2021