How To Use FreeCAD - Constraints | The Realthunder Branch | Sketcher Workbench | P. 3

this video is all about truly understanding free cards constraints what's up i'm jonathan and welcome to maker tales where i'm sharing my maker journey to help you go further in yours if you enjoyed this video i'll really appreciate it if you give it a thumbs up as i'm doing my best to help us all out this video is sponsored by fangs.com now let's get straight into it coming over from our last video we now know how to create a whole bunch of lines and how to do quite a few operations with them we have a preliminary understanding of what a construction line is we also know how to copy from one sketch to another we know how to copy within our sketch how to clone within our sketch and how to move an entire sketch and we know how to do a couple of references external and defining geometry references and if you don't know what i'm talking about right there i really suggest that you go and check out that video before you jump to this video this one is all about these lovely constraints both the geometric and dimensional we're going to go through each one of them to learn what it is and how to get started with it so let's quickly recap why exactly we want to use constraints well freecad is expecting from us to tell it where our lines exist within the 3d space because as they come in they're very free-floating and they can sort of do anything they really want they could even be completely not joined to one another or not do anything that we're expecting and freecad will tell us this by saying hey your sketch is under constrained and it has four degrees of freedom that's right this one little line has four degrees of freedom it might not really come across y so let's go over that this dot here can go up down left and right that's two axes so two degrees of freedom and this dot here can go up down left and right another two so this entire line has four degrees of freedom as we go ahead and add more rules more constraints to this line the degrees of freedom will go down until it's eventually a fully constrained or fully defined sketch but most importantly this definition is to put it within the 3d space so that freecad really understands how the sketch is put together and where it relates in the 3d space now with that recap done let's go through each one of these starting us off is the coincident constraint with the shortcut of c many people think of this as sort of a join but just be aware that there is no such thing as a join within freecad it's very much a constraint to one point to another point you select the parent you select the child you hit c and the child will go to the parent you can also do this across multiple children or multiple lines you select the parent you select the two children you hit c and that will bring them all to be constrained together the other way of using this is by activating it to the mouse hit c and it will follow your mouse once again you select the parent you select the child and they'll be constrained together you get a lot of coincident constraints using the polyline tool and you'll also get quite a few of them automatically when you're using any tool and go over a point you'll see you'll get this lovely little target looking thing which is the coincident constraint when you go over a point you'll also get a automatic coincident point when you go over the origin point of a sketch itself and that there is the coincident constraint next up we have fix a point on an object it has a shortcut of shift o it's sort of closely related to a coincident point but it has a lot more functionality you select the point that you want to be constrained you then select the line you would like to constrain it to and press shift o you are now constrained to that line but not only just that line but the projected outcome of that line as well you can also constrain a point to an axis so we'll activate it onto our mouse with shift o to show you the other way of using it we'll select the point we'll select the axis and there we have it you can do this to multiple points at a time as well so we'll bring in two lines here we'll select these two points and this line here we'll press shift o and you get it like that so now that we know we can do multiple selections and we can also do these projected outcomes you can start to see how this can get quite a bit more complicated and let me show you how we will get three lines like this i will select this point and two edges i mean two lines and we'll press shift o this point now turns into the intersection point of these lines another way of showing you this would be to create a big x like this we will bring in a marker i will select the marker and the two lines and press shift o this marker now turns into the intersection point but not only that if i pull this out it turns into the projected intersection point you usually get it when you're using straight lines on an edge like this because when you're using a curve up to an edge that's a different type of relationship and we'll get there in a moment so you'll also get it with the polyline whenever you're going up two lines it will show up like that and that there is this constraint then we have the vertical and horizontal constraint and they pretty much do what they say so horizontal h is the shortcut vertical v is the shortcut let's bring in a little bit of a polyline mess here to play around with fantastic we can just select a couple of lines here press h and they will be horizontally constrained and the same for vertical select a couple press v vertically constrained now we can do it by the mouse so we'll press v and you'll see that we have it applied to our mouse and we can just go and click in here or we can press h and do the same for horizontal so that's with lines here's where things get interesting you can also do it with points so let's select a couple of these points we will then press v and they will all be vertically constrained to one another and as we know points are basically just points of interest or markers so we have one that's always constant the origin point we'll select the origin point press v and now we are vertically constrained to the origin point of the plane of our sketch now you've just seen this done both to points and lines so means there is a little something to keep in mind here when you're creating a line there's two ways that you can apply the vertical and horizontal constraint to it you can just select the line press h and you'll get just one little constraint marker or you can select both the points and then press h and you'll get two markers now i would say usually the best practice is to have as little on the screen as possible because trust me sketches can get pretty overwhelming pretty quickly so i would normally say go for just selecting the line and that's how you're going to be the best thing so how do we get these constraints automatically well when we're creating lines when we create lines there's this little sweet spot as we get horizontal and vertical that the little constraint pops up like that there's a horizontal one there's a vertical one and we'll have the same for the polyline as well so the vertical and horizontal constraint are extremely powerful especially when you're mixing them up with other constraints as well next up we have the parallel constraint with the shortcut of shift p we'll bring in three lines to show this one off like so we will select two of the lines and use the shortcut of shift p and these will now be parallel to one another just in case you don't know what parallel means it means that these space between these two end dots to the line are going to be the same along the entire line that's pretty much what parallel means now you can do this to multiple lines at the same time so we'll select all three of them press shift p and they will all be parallel to one another and it also doesn't have to be to align i'll apply it to my mouse with shift p select a sketch line then select an axis and we will be parallel to the axis and that there is the parallel constraint then we have the perpendicular constraint with the shortcut of n i know it's a little bit of a weird one let's create two lines to show off the obvious of select one line select the other line press n and you we get a lovely perpendicular constraint if you don't know what that means it means that when you cross over these lines this is 90 that's 90 that's 90 that's 90. or the other way of thinking it is that when one line is going off like that it's going to be perfectly at a 90 degree from that line so that was with the shortcut let's do it with the mouse now press n to activate it to the mouse we'll select one line select the other line and perpendicular constraint you can also do it to an axis so we'll select a line select an axis and we have a perpendicular constraint now you can't do this to multiple things at the same time but you can do this operation you can select these two lines select this point here then we'll press n and we get a perpendicular intersection point so these two lines crossing over are going to be perpendicular to another and right here we will have a point to a line or to an object very much when we were first covering it at the beginning of this video now the perpendicular constraint can also be a coincident constraint yes things get a little bit weird let's create a polyline start the line off press m once to get the perpendicular behavior click it on let's cancel that and you'll see we have one perpendicular constraint and this is joined together but where is the coincident constraint well this is a perpendicular coincident constraint and just to show you i'll select it delete it and you'll see we'll be able to pull them apart you can then select the two markers here press n and we get a perpendicular coincident constraint and that there is the perpendicular constraint and next up we have the tangential constraint with the shortcut of t now this is a gigantic topic so i'm going to do my absolute best to really condense it down in case you don't know what a tangent is let's bring in a circle let's then go and bring in a line i want this line to meet this circle well that right there is called direct tangency i'll select them both and press t this is now tangentially constrained and i can even pull this out and it does the whole projected line thing we can then press t and activate it to our mouse and i can go from a curve to an axis and i can do it again curve to an axis and you're starting to get the understanding of what exactly tangency is okay so this is line to curve tangency we can also do point to curve tangency so i'll delete this will bring in two circles because i want to show you the difference between a fixed point to an object and point to curve tangency so fixed point to an object we know the shortcut is shift o and this sort of does that yeah sort of make sense right okay well let's go point to curve and then go t and you'll see an instant change here it sort of just follows around the circle or the curve continues on on that line okay point to curve we've now got line to curve what about point to point now point-to-point tangency is probably the most used case within card design so i will create these two arcs and i want them to be sort of fluidly connected you might think okay i'll select these two points i'll press c for for a coincident constraint oh but things break pretty quickly i can get sort of close what we're really looking for here is a tangential coincident constraint very similar to the perpendicular one we can do it with tangents so let's undo that connection there we'll select both of these points here we will press t and now we have a tangential coincident constraint you can see we only have one constraint here and this is what's keeping it all together as well so that's that so we have curve to curve what about curve to line well let's bring in a line let's select the two points here and we'll press t and there we have it a nice simple line tangential constraint going on coincident tangential constraint excuse me okay but what happens if i accidentally forgot to add this tangent constraint and i already had this set for instance as a coincidence point so select this go c and now i really want this to be tangential well i'll press t i'll select this edge here and i'll select this edge here okay great i fixed it but take a look we now have a coincident constraint and a tangent constraint now there's nothing really wrong with that but it might not be super clear to you and later on it can bring up a little bit of problem but in reality i just want you to be aware of this and you can't just go in here and delete this because now this is turned into a different type of constraint this is turned into our curve line constraint as you can see so just be aware as you're building things out it's probably best to just straight away create it as you want it to be made okay so that is the point to point what about line to line well you can do line to line tangency it's a little bit of weird one and you might not have expected it i did not mean to add that horizontal constraint there we'll select those two there press t and here we have it this is two lines that are tangent or it's also known as co linear so these are co-linearly constrained all right and lastly we have a point tangency so i will create two circles here and we already know that we can select both of these and press t and they will be tangent right there touching each other but i have no way of controlling this touching point if i want to control this touching point i need to create a marker create a point i will select the point then i'll select the two curves and i'll press t and now i have a little point in the middle of this tangency so that i can control it and that there is the tangent constraint it is extremely powerful and it gets used all the time in technical drawing a nice easy one now with the equal constraint and it has the shortcut of e i'll bring in two lines one long one short and two circles one small one large and two arcs one smaller one and one much larger one as you'd imagine e for equals makes things equal i'll select both of this press e and they are now the equal length i'll press e to activate it onto my mouse i'll select one and the other and they now have the equal diameter i'll select one and the other and they now have the equal radius and it is very much the radius because i could make one a lot longer than the other one but the radius is still the same and that there is the equal constraint next we have the symmetry constraint and it has the shortcut of s now we've done a little bit of symmetry when we're doing some symmetrical copying along an axis but this one is a little bit different because we need to have everything so we'll create our axis of symmetry we will then create two circles that we want to be symmetrical along that axis i'll then select the two points and the line of symmetry and the order does matter and then i'll press s and lo and behold we have symmetry great let's do that now with the mouse so i'll press s activate it to the mouse select the two points and instead of clicking on this line i'll click on the axis and there we have the symmetry along an axis but you can also do this along a point so i'll select these two points here i'll select the origin point press s and now we'll get radial or orbital symmetry however you want to think of it you might think that that there is all that symmetry has to offer but there's a little bit extra so let's create three lines here one two three and another one over here let's create a circle and what i want to say is i want to have this circle in the middle of that line no matter what well i can do that i'll select the point select the line press s and now this is centrally confined to that line and you can do that with any point we can select this point here and the line over there press s and now no matter how long or short this line is it will always be in the middle again the order does matter so if we were to do something a little bit like this and then create a point here make sure you select the two circles first and then that point because if you do it this way one two and three you've got a completely different outcome now this could be an outcome you want because that's going to stay on that end this is going to stay on that end and that will always be in the middle of those two points but that there is the symmetrical constraint next we have a little bit of a weird one which is the block constraint now i think it's a little bit misleading to call it a constraint so i call it the block tool it has no shortcut and it's very niche to the use case i will show you now why when i've been doing all my examples here i'm sure you've realized that while i go here and apply a constraint all the lines move all over the place and it can be quite annoying when you've got a rough shape going on so that's what this block tool is all about so i can go here apply it to the line that just moved there and now i cannot move this in any way whatsoever however i can go over here apply my constraint that i had last time and into scene it has not moved it at all now i go back and i delete that constraint because you do not want to leave these block constraints because these leave under constrained lines in your sketch and that's a big no so we'll delete that and do not be fooled by the green because this is still under constrained but that there is basically the block tool in a nutshell is to help you and aid you while you're doing constraints to your sketch so if you don't already know thanks.com is basically a machine learning 3d model search engine and community with over 3 million free models to download it really is an awesome place to upload your files firstly fang supports more file formats than i care to mention second is a great place to collaborate privately for free plus it keeps track of all your public files as things machine learning tech will point out and link all the remixes lastly if you really want to check a model in more detail you can use their app-free augmented reality viewer to really examine a file before even downloading it so after this video be sure to go down to the description and click on that link to check things out moving swiftly on to the dimensional constraints we're already beginning to understand these we know that this is a horizontal dimensional constraint this is a vertical dimensional constraint this is shift h shift v but what on earth is this padlock well let's bring in a rectangle to show you it it's a very powerful one nice and simple but it's very specific use case we'll select this bottom right hand corner we'll select the padlock because it does not have a shortcut and it instantly applies both a horizontal and a vertical constraint now you can now double click into these and change the values you can also click between these two points and press this padlock and it'll create it there and you can see very quickly we now have a fully constrained sketch just be aware don't go about over constraining your sketch and pressing the padlock on silly places like this because this is going to give you a zero and this means that this has redundant constraints and that's not something you're really looking for so in very particular use cases this can save you a lot of time now let's go through our linear dimensional constraints we already have an idea of what the horizontal and vertical constraints are we have shift h and shift v let's go and bring in a rectangle and show that once again we can select an entire edge press the shortcut of shift v or we can press shift h apply it to our mouse and go from point to point and vice versa they're basically the same way of using it now there is a little bit of a strange thing that can happen here let's go with shift h on our mouse and let's go from one point to another point like this don't get confused this is not the diagonal distance this is the horizontal distance between those two points if you want the diagonal distance that's what the next constraint here is for i like to think of it as the diagonal distancing tool or diagonal dimensioning tool with shift d so we'll select the two points that we're wanting this distance on we can press shift d and we get the distance you can also press shift d and get it on your mouse and go from one to another and that's another way of doing it the thing that's very different about this tool is it lets you go from a point to an edge and this is extremely powerful when you're wanting to dimension offsets for instance very powerful indeed however be careful i don't like to use this for things like my horizontal and vertical why i'll show you right now i'll set a vertical constraint right here and now i can tell within my constraints okay this one here is one of my diagonals diagonals and this is a vertical but i don't know which of these diagonals is a horizontal constraint so just be aware it can be very powerful but it's usually best to use the correct constraints for the correct dimensioning that you're looking for and that there is the linear dimensional constraints coming up we have two that are pretty self-explanatory which is the radial and diameter constraints let's bring in two circles and we'll also bring in two arcs as there's sort of a best practice here so with arcs you should really define them by radiuses so let's click on the radius button we'll click on the arc and now we get a lovely radius right here there is a hidden shortcut and the hidden shortcut is shift r i'll select the arc press shift r and now we get a lovely little radius with that shortcut now it's a little bit like the clone copy tool in the sense that you can redefine the shortcut by changing the tool so i'll go over here click the diameter constraint click on the circle apply a diameter cancel the diameter select the circle and now when i do shift r we're going to get a diameter constraint not a radial constraint and just to show you that it is that i'll delete this lovely constraint here select the arc once again go shift r and now we get a diameter constraint so just be aware of it it's very powerful to use these shortcuts but it can trip you up especially when you have two different ways of dimensioning things and they should be dimensioned in different ways anyway and that there is the radial and diameter constraints and probably the simplest of all the dimensional constraints is angles with the shortcut of a let's create a polyline here that has a one angle in it and we will select the two lines and press a and there we have it a nice angle set there we can also do this by the mouse so we'll press a apply it to our mouse select the two edges and we get an angle applied right there and that there is the angle constraint now i'll be honest with you i want to completely skip over this this is basically how to create a refraction law or snell's law by all means to go and look it up online this is not something that i know how to do i've tried my best but if you want to know how to do it i'll show you you create a line create another line create another line then you're going to select the two points and the medium of reflection we will then click snell's law put in whatever ratio you want and wa-bang i do not understand this relationship whatsoever but if you do there you have it and now we've reached the end of the constraints all that's left are two little tools here this one here turns all of our dimensional constraints into reference constraints what's a reference constraint well remember how we've got our construction lines it's sort of the same aspect let's bring in a rectangle here we'll select this edge here we'll go shift h and we get a lovely constraint now remember constraints will put down our degrees of freedom because we're starting to lock things down and we can't move this anywhere but if we select this and then we turn it into a reference one we can still move things and our degree of freedom go back up so these references are very much just for you to know what the distances are they do not add anything else to your sketch they are very much there for you just to know some distances so if you have nothing selected you can click this and then all of them will become references so when you use them within your sketch they're going to come up as reference distances now the very last one here is to deactivate and activate different constraints i don't use it that much but i'll show you how it's used you select it then you click here and it deactivates it it grays it out and makes it really hard to see and then you just have to be very careful where you're selecting you select it once again and turn it back on of course if you really want you can go and click within here and this way you can go and deactivate and reactivate them pretty quickly but you have to come back in here and select them once again and then go back over there that there is all the constraints and in the next video we're gonna really start to pull things together well done for getting through that monster of a constraint video it is no easy feat even if you do know them and if you don't know them wow you really have blown me away especially with some of those geometric constraints because freecad and the way that that works it can be quite weird at times but trust me all of this will slowly but surely slide into place a huge thank you to my patrons you guys are absolutely awesome and it really does mean the world to me is what makes these videos possible and if you're enjoying what i'm making here and you think i'm worthy of your support i would love it if you'd consider supporting me on patreon thank you for watching keep making and let the quest continue

Channel: Maker Tales

Views: 6,064

Keywords: freecad, freecad tutorials for beginners, freecad tutorial, freecad 0.19 tutorial, freecad sketcher tutorial, freecad 3d printing, free cad software, free cad software for 3d printing, free cad, free cad 0.19, fusion 360 to freecad, fusion 360 alternatives, cad beginner course, cad beginner tutorial, cad beginners guide, beginner cad software, cad beginner, 3d modeling for beginners, realthunder, how to use freecad, drawing, technical, sketching, Constraints, rules, dimensioning

Id: hqPA_AfVzmo

Length: 25min 46sec (1546 seconds)

Published: Fri Aug 20 2021