FreeCAD For Beginners p.2 - Parametric Modelling

welcome back to another video and today we're going to talk about parametric modeling probably the most important thing you can ever learn for cad this video is a continuation of the last one so if you haven't watched my free card for beginners video make sure you go check that out first and then come back to this one so what is parametric modeling well it's a powerful technique that you can integrate into your workflow and what i'll give you today is a visual demonstration of what it is why it's useful and why you should continue to use it in future designs if you can implement this and you understand it it's going to save you so much time later on down the road especially when you start designing really complex models so let's get started and i'll show you how to use it so this is where we left off in the last video we created this kind of cube thing with a pocket in it and then we fill it at the edges to make you look a bit nicer and if you remember in that last video i told you that you can easily make changes to your design just by coming up to your part tree and double clicking on the sketch so if we go ahead and do that you can see we're back into the sketch we can see our constraints our dimensions i said that if you wanted to change one of these you had to go in double click it and enter in a new value and that can get quite time consuming and tedious over and over again i wouldn't be really cool if there was one place where we could just enter in a value and our whole design updates that would be awesome and that is basically what parametric modeling is it's a way of creating your designs so that the design kind of adjusts to itself based on a number of parameters so let's implement parametric modeling and you'll see exactly what i mean so first of all we need somewhere to put our parameters and we can do that inside of freecad so make sure that you close your sketcher so we're going to update close if we come up to the workbenches drop down here at the top we want to click on spreadsheet that takes us to a completely new workbench and we've got a bunch of new tools again at the top now if we come up to spreadsheet click on create spreadsheet notice in our part tree here on the left it adds a spreadsheet for us we're going to right click on that spreadsheet rename and we're going to call this parameters once you've renamed the file if you double click on that file parameters it takes us to a little spreadsheet and this is where we're going to enter in all of our parameters let's go back to our sketch and have a look at exactly what dimensions we're going to use and what parameters we're going to need so once again we double click on our sketch takes us straight back in and we can see in here we've got a square we've got a width and a length but remember we also have these other parameters here to help keep it central so what i'm going to do is go back to the spreadsheet just to let you know as well on the bottom of the application you've got this toolbar with a bunch of different tabs and instead of updating and closing and going back and forth all the time you can just click on these tabs and it quickly jumps you between the different workbenches so we can click on parameters and we're straight back in here so looking at this we're going to need two parameters length and width so what i'm going to do straight back into the parameters tab in the cell a1 i'm going to enter a name for the parameter which is going to be width and we're going to make that 50 because that's what we're using currently so we just enter in 50 we have to right click on the cell that we've entered the value in and click on properties now if we come to alias this is where we're going to have to give the property a name we've already put a name in the spreadsheet but that's just for our reference in order for free card to know about this property you must give it an alias so we're going to put the same thing in here we're going to put which if you click on the tab here display unit you can enter a value in here as well for whatever unit you're using so i'm going to just enter mm for millimeters hit ok and you can see now in our spreadsheet the cell is turned yellow and we can see that we've got a value of 50 and we're using units of millimeters the other parameter we need is length so once again we double click on the cell we're going to enter in length click on the cell in the next column we're going to enter another value in here for that parameter which is going to be 50. if we right click on the parameter properties again display unit we're going to use millimeters and we need to give it an alias which is going to be length hit ok and there we go you can see that those have turned yellow and that means they're active so we just click update then come back to our sketch tab by clicking on the bottom here so let's make use of those parameters we need to now change these values we've got here to the aliases we gave for our parameters so if we take the width parameter here at the top we're going to double click it here it asks us for a numerical length value but we're not going to use that there's a little button here that you can click over on the right and that brings up a formula editor now in here we can reference our spreadsheet remember we named our spreadsheet parameters so if we start typing p you'll see parameters is already in the drop down so if we come down to it notice it's now changed to parameters dot and this is where you put in the alias so we want width so we're going to enter parameters dot width i notice this all suggesting it for you because it kind of knows that's what you want to pick choose width and notice the result changes to 50 because it's referencing that value we gave it in the spreadsheet so if we hit ok notice that our dimension now has turned orange and that means it's referencing the spreadsheet we're going to do the same here for the length so we're going to double click on our length parameter once again we hit this little button off to the right brings up the formula editor we're going to do it once again so we start typing p we go down to parameters p dot length suggests it for us we hit enter the result is 50 hit ok and now both of these are using our spreadsheet parameters but remember we've got this value here that's keeping our square centralized to the origin of the workspace now you might be thinking well surely you can just create a new parameter for that as well well yes in theory you could but it'd be the wrong way to do it what we need to do is make reference to the other parameters this distance simply needs to be half of the length or half of the width so for this one it's the width so we're going to double click on this parameter if we hit that little button once again we can type in here parameters dot width now hit a space bar and do the divide sign divided by two notice the result is changed to 25. so this formula editor allows you to do arithmetic operations and it's extremely useful and this is what parametric modeling is all about we're using parameters to define other values so that our design it almost becomes smart right it knows to update those values and make our lives a lot easier once you've set that you can hit ok and notice now that one's turned orange as well because it's referencing our parameters we'll do the exact same thing for the length so we double click click that little button type in parameters dot length space divide sign divided by two hit okay now let's do this exact same thing for our other sketches remember we created a little pocket before as a circle so if we go back into pocket double click on the circle sketch we set the diameter of the circle to be 12.5 millimeters so let's go and create a parameter for that as well so back into the spreadsheet we're going to create a parameter called pocket diameter so we're going to type in here pocket diameter we're going to enter remember this was 12.5 so once again 12.5 right click on the value properties display unit millimeters alias pocket diameter okay now if we go back to our sketch once again we can grab the circle sketch double click on that parameter hit the little button type in parameters dot pocket diameter we're going to hit ok the value is 12.5 we've now set that up as a parameter as well let's update and close the sketch and next up we need to set a parameter for our height remember we created a pad or an extrude to create the height on this so if we go into our parameters again we're going to set up a height the parameter is going to be 50 millimeters because remember we've got a cube right click properties we're going to go to display unit millimeters alias height okay and now if we go back to the parametric modeling tab this time it's a little bit different we created a pad or a pocket so we don't have a sketch to go into remember we create the pad and we named it cube so if we click on this here notice there's a table that pops up in the bottom left and it has a bunch of values in there but what we can also do is double click on cube and it takes us straight back to this menu where we were able to enter in a height value so once again click on the little button we're going to type parameters dot height the value is 50 hit ok hit ok again and we go back to our model tab so notice that we changed our value and our design hasn't updated to what we knew it to be before it's kind of just still in this cube every time you click on one of these previous actions here like cube pocket fill it it's kind of like a timeline so you're kind of stepping back so if we double click on pocket and we just hit ok we've now jumped to that stage where we created a pocket again we want to be to the latest stage so we want to go to fill it hit ok and we're right back to where we were to create that pocket we had to do a cut into the cube and we can set a parameter for that as well so if we go back to the spreadsheet we enter a new parameter we're going to call it pocket cut we're going to enter a value in there which i believe it was 12.5 right click properties make sure that you set the unit to millimeters alias for the cell once again we'll do pocket cut hit ok and there's our parameter if we go back now to our part design workspace we can double click on pocket and let us choose that value we just want to enter parameters dot pocket cut hit okay and we have our parameter now remember we need to update so we go down to fill it hit okay and that updates us back to our most recent spot the last thing we need to create a parameter for is our corner fillets and we can do that quite easily so if we go back into parameters create a new one corner filler we're going to make this 10 millimeters right click properties display our units set the alias you always have to set the alias so we're going to do a corner fill it okay come back to our model double click on the corner filler which we could also rename so let's do that we'll right click rename corner fill it that just makes it easier to identify which features you've got within your part tree so let's double click that once again we can click the little icon we're going to enter a value in there hit ok update our design and there we go we've set up all our parameters and you might be thinking well that was a lot of effort to go back through and change them but the mindset you have to have is that you'd be doing this as you go through a normal design free card isn't the most user-friendly something like this is so much easier in fusion 360. freecad does need a bit of work in my opinion in kind of speeding up the workflow but i mean it is free and it's not that bad once you get used to it and here's the fascinating part so now you're going to see the power of parametric modeling and why it's so awesome so let's say we created this cube we're not happy with the width and the length all we have to do is come into our parameters we can change this value let's make it a hundred so let's double it up let's change the length to 100 as well now we're going to go back to our model workspace and it updates for us just like that by changing two values now if it didn't update for you come up to the part component tree up here we're going to right click click on mark to recompute or hit f5 on the keyboard and that should recompute everything and update your design and just to show you what this is doing why it's an intelligent way to design if we go back into our square sketch notice the values have updated on their own we set the length and the width to 100 and it's kept the square centralized because we also set up these values to be half of the width and the length so they've updated as well to 50 mil so if we close back out of this let's say we want to update the the circle radius so let's do that as well let's go into parameters let's grab the pocket diameter now let's change it to let's go back to our model workspace and there we go it's updating for us again now let's change the corner fillets so let's go into parameters corner fillets let's make it 20. enter back to our model workspace and just like that it's done it's so much easier than going into the sketch double clicking changing the values going into each of these operations changing the values i think you can see just how powerful this is and why it's so so important never cut corners always do card the right way most of the tutorials out there are not going to show you this because it takes a little bit longer and it's a little more difficult to get your head around but if you get your head around this you're going to be awesome at cad trust me i hope you learned something today i hope you're enjoying these videos i'm really enjoying making them personally because i feel like i'm making card a lot more accessible to more people fusion 360 is my favorite tool by far but not everyone has access to it and that's completely fine so i'm going to keep making these videos for those of you that don't have access to things like fusion 360. but as always thank you for watching subscribe for more videos if you want to request a tutorial leave a comment below and i'll see you in the next video

Channel: thehardwareguy

Views: 97,519

Keywords: freecad, freecad tutorials for beginners, freecad tutorial, freecad 0.18 tutorial, freecad part design tutorial, freecad 3d printing, freecad vs fusion 360, free cad software, free cad, free cad 0.18, fusion 360 alternatives, fusion 360 alternatives free, cad beginner course, cad beginner tutorial, cad beginners guide, beginner cad software, cad beginner, freecad course, free cad course, freecad parametric modelling, cad parametric modelling, cad course, parametric design

Id: RNCsazKxviQ

Length: 13min 41sec (821 seconds)

Published: Mon Nov 02 2020