2D Sketch Constraints, A Beginners Guide | Inventor & Fusion 360

ladies and gents welcome ATF is as a long-overdue much requested video all to do with 2d sketch constraints I've got a spare half hour I thought right let's do it let's get it out the way and done for all the newcomers to inventor who need to understand these sketch constraints a little bit better because I remember what it was like look at them and go what their hell are these things I have no idea what any of them mean so we're going to start by doing 2d sketch we're going to drop the 2d sketch onto one of these origin planes these are your starting planes for new 2d sketches think of them as bits of paper so I'm going to select the XY plane and that gives us a sketch plane a bit of paper if you will placed on to that origin plane where we can now start drawing lines are circles rectangles and the like and then you've got this cluster of buttons up here these are your 2d sketch constraints and I remember looking at them in I remember what you're thinking right now is you need to be part of some secret Club to understand what they all mean I mean like what that what's that thing there looks like a shoestring no idea what it means so I want to take you through what all of them are what they do each of them when you'd use them and what the four but to help understand why you need them in the first place what we're going to do is jump over to AutoCAD and look at how things used to be done back in the olden days before AutoCAD even had to deccan strains which it does and we'll look at traditional drafting so what in AutoCAD what you would do back in the day is you would say draw a rectangle and let's say let's make it a square hundred by 100 and then we'll put a circle I don't know what the midpoint of the top and we'll make that 20 and then we'll do another circle at the midpoint of the bottom line and make that 20 and then we'll trim watch him all that out there okay so that gives us a very basic kind of plate design maybe it's like a metal plate with two flaps top and bottom if you go on a proper autodesk training course it'll reseller all or something like that you'll hear the expression overused design intent right you capture the design intent we're all about capturing the design intent whilst the expression makes me cringe somewhat there is some merit to it and that if your design intent if you intend for this design to be a certain way you put in constraints to force the objects to respect your design intent for example these two semi circle objects here this one here and then this one here if you intend for them to always be on a centerline well back in the old days all of autocad you couldn't do that the objects were completely independent of each other so if there was a change in the future and this object needed to be moved maybe 50 mil across to the left or 20 mil across to the right then this one here just stays put but the design intent is that this one here should always be on a sent line with that one so you'd use a constraint to force them on with sent line and then when you move one the other moves with it that's the whole point of 2d constraints similarly that line here stops here you see there's now a break between the the top edge of the rectangle by the square and then the the end point of the arc well you can place a 2d constraint in Inventor to always keep that point there touching that point there so that will never cause a break when you move objects around so back in the olden days we just didn't have constraints but nowadays we do nowadays we do like that I do like that new AutoCAD selecting window but that's nice right back over to an vendor so within vendor we can use 2d constraints to plug in this intelligence into our sketches to stop things from falling apart you can't get away with doing sketches without creating 2d constraints but it's going to be messy it's going to be dodgy flaky and in the future things are just going to fall apart you can have a bad time luckily though invent it does help you out by giving you constraints as you're sketching for example if we draw a line from just one random point to another and if you just move your cursor down so it's roughly horizontal can you say it's snapping they're snapping at the horizontal and if you look at both the little tooltip that says zero point zero zero degrees there's a square icon there with a horizontal symbol I know it does look like an upside-down Loch Ness monster fin but it's actually a horizontal constraint being automatically applied to the line so when you click this point here inventor is forcing horizontal constraint on to that line therefore this line will always be horizontal so when I click the line you can see the glyph there that's letting you know that that line is forced horizontal by a horizontal 2d constraint so if I grab the endpoint of this line and move it around a cut put the mouse in circles it will never ever no matter what happens in the life of this line it will never ever be anything other than horizontal and that's the whole point 2d constraints that's the whole point of them right so we'll do something similar to what we had in the AutoCAD sketch so let's look at the the front of this sketch so we're looking straight down on we've hit the front face the viewcube and we'll do it we'll do a rectangle let's start with a rectangle 100 tab 100 and then we've now got a whole bunch of constraints already in here and we've done nothing we've done absolutely nothing the first constraints that it's applied are yellow you see these little yellow squares at the endpoint of the line those are called coincident constraints a coincident constraint tells inventor that two endpoints are always going to be touching each other and not necessarily always endpoints either you can make a line coincidentally constrained to another line and it just means that object will always be touching that object so for example a straw another line here like that and if I want that endpoint to always be touching this line don't don't no we're not in the midpoint not in the endpoint I just wanted to always touch that line well then you go up your sketch constraints and you find the coincident constraint so go do that so the coincidence exactly exactly you're looking at the sketch palette and you go and I don't know which one the coincident constraint is because they're not labeled so what I find is for a new color the best way to interact with constraints from day one just whilst you're learning is to right-click go to create a constraint and then you get them all here but they're named so you can get a little word next to all the icons and it'll tell you what they are as opposed to just having a guess what they are from the top palette so if you right click go to create constraint and then select coincident select the endpoint of the line click that and then click this line here and then that will create the yellow square and now the two objects are always going to be touching each other you can now no longer pull this line off of that square it's always got to be touching it even if it's upwards it's still coincident to that it's still in line doesn't have to be actually on it it can still be in line with it so that's the coincident constraint invent it will automatically at square corner points if you do other rectangles slots as well for example so if we do a center to Center slot this coincident constraints created where the arc meets the straight horizontal line on the slot those are automatically created for you again for a slot here we go we've got some tangent constraints automatically placed at the four points around the slot invent and knows that you're creating a slot therefore this arc here should always be tangential to the top and bottom horizontal lines so you can get away with not manually creating them but there are times where you do need to manually create them so back over to the to the Oracle example another constraint that we've got here are these two here now you might not look at them and think of them as being constraints but they are actually constraints they're called numerical constraints aka parameters aka dimensions but it's still a constraint you are numerically constraining that line to be 100 millimeters long that's what it means you don't see this on the drawing this one here you don't see that on a drawing you don't see on a print it's a numerical constraint you are numerically telling in vendor to always always no matter what happens throughout the rest of this models life always keep that line at 100 mil and it will be and drag it around it's now forced 100 mil if you select that dimension hit delete on the keyboard that line is now free to be any length at once but as soon as you say create a dimension on here and then make it 100 mil long it's numerically forcing that object to be that length so it's still a constraint it's just presented in a different way okay so some other constraints that we've got will do the will do the Oracle example so we'll draw a circle and then what we'll do is we'll snap to the midpoint of the of the top edge and that creates a constraint that creates a coincident or constraint at the center point of the top edge of the rectangle see that object little glyph goes green but to let you know that there is a snap at the top edge so just like AutoCAD you can right click it works in a little bit of a different way but you can go point snap and then midpoint and it'll let you snap to the midpoint of that line which is which is nice that's nice it just saves you having to manually search for the midpoint yourself and we'll type in watch it was a radius of 20 so we'll do a diameter of 40 and you can see the yellows where's creatives coincidentally constrained to the top edge of that that square so now as we move it around that circle is always placed at that point no matter what happens we can move this around with the left mouse button and it's it's staying put it ain't going anywhere so yeah it's that's that's kind of the whole point of them and we'll do it again at the bottom circle right click point snaps midpoint there and then we'll do 40 ok let's do a bit of trimming as well just like we did in order cats will hit trim trim trim and trim just be aware if you do any sketch modification commands such as trim extend scale any of those it can break the objects and break the constraints it's forcing you to remove entities from within the sketch which can therefore remove wear constraints have being applied to so if you've constrained something to align and you trim that line away though that constraint is going to break because that line is no longer there so trimming objects can cause some things to break in as you can see it's done just that we've broken this top edge and this bottom edge into two halves so this edge is now no longer one straight horizontal line it's not been broken up so this is where you would additionally create 2d constraints manually not apply in those 2d constraints manually would be devastating to the sketch it just wouldn't work so we need to now add in some 2d constraints to make sure that we capture the intent of this design and that's where the rest of these constraints come in so what we'll do is we'll start with making sure that these two arcs are in line with each other because at the moment they're not you can see these two arcs can move side by side to each other completely independently to each other so you've got to think yourself well what kind of constraint do I want here now there's no such thing as a centerline constraint the way you can do is think well these two objects here are needing to be vertically aligned with each other I want that point to be directly vertically in line with that point there so I can right-click create constraint and I can go to that vertical right so what you then do is you click the center point of the circle click the other center point of the circle and then that will vertically align those two objects together hit escape and now these two semicircles are always going to be vertically aligned with each other there's still a bit of work to do though so we need to try and figure out how to get these two lines here and these two lines here to stop being completely higgledy-piggledy and monkey so what you can do there is there's a couple this there's never any one right way of doing it there's multiple different ways of doing this but you could think to yourself well these two lines should be horizontal to each other so you could right-click create a constraint horizontal click these two lines here and then you'll see it gives you an error it says whoa hang on a minute you've just asked me to make the line horizontal you just click the line you're asking me to make the line horizontal it's already horizontal the problems not that the line isn't horizontal it's that it's not horizontally aligned with this one so you are right well then there's another way of doing this you can say make the endpoint of that line horizontally aligned with the endpoint of that line and then that brings them in line with each other now I'm going to press control and Zed here and undo that because there's a different constraint for this type of scenario you can right click go to create a constraint and you can select something called co-linear collinear places two lines onto the same axis and don't necessarily have to be horizontal or vertical so if you select collinear you can pick that line there and then that line there and then that will put them on the same axis and what I mean by the don't have to be horizontal or vertical is if I draw a separate line here and then say a separate line here and then we go right click create a constraint I need to press escape so out of the line command create constraint collinear where is he going where you go and where they gone that on there make these two lines collinear they're now on the same axis as each other so that's what collinear is it's that it's actually a really good one that is a really good one to know doesn't always apply just the horizontal and vertical it can be any angle but two lines will then be on the same trajectory if you like okay right so what else do we need to do here well looking at the design you'd think right okay what what other kinds of design intent do I have in the schedule I know that this edge here and this edge here need to be the same length and I also need to apply the collinear constraint at the bottom as well not forgetting that so we're going to go collinear and then these two lines here so I think this line here and this line here neatly the same size they need to be equal to each other so you can select the equal constraint pick these two objects here and then that makes those two lines equal and because there's a whole bunch of constraints down here almost mimicking what's going on up here then this line here and then this line here are now not really by default but as a result they become equal themselves and then from that point onwards you might find you get to a point where you you've got no more room for 2d constraints you've placed as many 2d constraints as you need to the only thing left now is to place some dimensions on to get the sizes right that might be what's left to do but in this case there's not there's a few more that we can place so for example the the ark you can see it's it's completely there it's it's constrained it's in the right place but it's free to move around it's not really you know the center point of the arc isn't in the right place so what we can do is we can say right I need this octa just be a perfect nice tangent are coming out from the the profile of why the plate this would be so I want this center point here to be in line with this top edge so we can right-click we can go to create constraint horizontal I want this center point to be horizontally aligned to there same at the bottom I want this point here to be horizontally aligned with there and it forces the object to be horizontally aligned to that other object and it will be indefinitely okay the shapes pretty much done now the best way to check that your shape is done is to hold the left mouse button down on any point and then just drag it around if your object doesn't break and fall to pieces then you're pretty good a couple of other things to do is to place the objects central on the sketch so you don't want this is just a best practice thing you don't have to do this but it's just the best practice thing don't leave your sketch just floating somewhere up here you see this little yellow dot here that is the center of the model think if your bedroomm think if your front-room think of the absolute central point between all the walls and the flow on the ceiling that is this dead center of your living room or bedroom that yellow point there is dead center of the 3d model in model space if you like so we want this to be symmetrically placed around that center point around about there so it's symmetrical that way and it's symmetrical that way so how do we do that how do we get it to be symmetrically aligned to the center of the model well it's pretty simple you just use two D constraints again you want the center point of this line here to be in line with the center point of the model so you go back T constraints create a constraint horizontal and you can pick the midpoint there and select the center of the model right click again create another constraint vertical between the center of the model and then the center of arc notice the lines have got a different color as well when your lines of green that means they can move in some way shape or form they have a degree of freedom within them whether it be to change size or change position whenever the green they can still move when the line goes purple or blue based on what color scheme you use and of course if you changed in vendors default color scheme you might have different colors here but when your lines change color usually to a darker color that means they are fully constrained and you can check down here at the bottom in an invalid is saying things are fully constrained there is no movement anywhere in any of the objects everything is fully tied down so we've covered quite a few of the 2d sketch of the 2d sketch constraints there but there's a few other ones which we haven't touched on yet so what we've looked at so far we've looked at we've looked at coincident we've looked at collinear we've looked at equal horizontal and vertical so there's a couple of others one being perpendicular so perpendicular is when you want a line to be perpendicular to another line so for example we can draw Ashley we're going to do an extra bit on the outside of this plate so we can draw a line coming out from here and if you want this line to come out at a 90 degree angle from this line well then you'd make it perpendicular so you'd right-click you got to create constraint perpendicular that between that now you might be thinking yourself well why don't you just make that horizontal well because this line here might not be vertical this line here might be 45 degrees you need still want that line to be perpendicular to it so that's when you would use the perpendicular constraints or for example line another line right click create a constraint perpendicular between here and here therefore if this line suddenly changes angle this line here is always perpendicular to it so sometimes there's right and wrong ways of doing something again it's all about you using your brain to decide right that line needs to always be a certain way in relation to another line or another object then that one is perpendicular right well so we got we've got parallel ok parallel is when you want to lines to be parallel to each other so we might have a couple of objects here let's say for example let's say we've got try to think well well I will just use the example of two lines to keep it simple so we've got two lines running alongside each other and we want them to always be at the same angle the exact same angle is each other running parallel alongside each other so you'd right-click create a constraint and you'd say make that and that powered out to each other you get the little parallel glyph there and then when you move or change the angle of any of those lines they will always remain parallel to each other so it's totally different to making two lines horizontal or two lines vertical it's forcing two lines to be parallel to each other now you would very rarely do that with just two lines you would typically tend to have maybe I don't know as some kind of shape so would have a profile which is something like this and you might have a sham third edge on the on one side of it and you're creating a feature inside that plate which needs to be in line with the Sham third edge so you might be drawing another feature over here somewhere and that needs to be in line with the edge of a 3d model the edge of a sheetmetal cut anything like that it could be it could be anything but it's always when you want something to be parallel with something else click the two lines and they will always now be parallel okay so that's a parallel constraint well as we got we've got a couple more color we've got tangent tangents are pretty straightforward one so let's draw a line straight down and then what we'll do is we'll create an arc from here this endpoint so our arc is going to extend around there and then we're going to draw a line coming out from the arc maybe up there right so the tangent constraint forces an arc and a line to be perfectly tangential to each other so it's almost like that arc becomes a circle and it's quadrant point is in being the endpoint of the line it just comes out at a perfect circle from the endpoint of the line so what you do is you're right click it select create constraint tangent pick the arc pick the line and that now makes about a perfect circle coming straight out of that line so that point there would otherwise be the quadrant point of that circle it'd be the left hand side quadrant point of that circle same goes for down here we can go to right click create constraint tangent select this line and then this line here and that's now giving us a perfect tangent you can automate tangential constraints though you don't have to do those manually you can automate them so for example draw an arc select the endpoint of the line pick the second point of the arc and as you move the cursor down you can see it's going to snap where it would be tangential to that line so it's pretty easy to do automatic tangential constraints all right well else we got we've got concentric right concentric allows you to place a circle or an arc concentric Li positioned to another one based on center points really so we could do a circle like this it's a bit big maybe that big right right click create a constraint concentric place that circle and then that arc and it will place them under the same center point so this circle is now sharing the same center point is that arc because they are concentric to each other so that's concentric and constraint what else we got we've looked at collinear we've looked at equal we've looked at horizontal vertical fix is a bit of a cheat but it's sometimes useful a fix constraint is for example when you're doing something like a remove your construction line so you draw a line you'd select it make it a construction line now that construction line is able to be moved around and you don't really want to concern yourself with having a place dimensions and 2d constraints on a construction lines what you can do is just say right create a constraint and then I want to fix it select fix pick that line it just goes blue it's just now fixed it can't move it can change size because it's not a numerical constraint but in terms of its position its fixed it cannot move anywhere and you can do that actually for any object really so there's a square right click create constraint fix and then select any of the lines here and rather than having to do horizontals and verticals if you're happy that the object is it should be right now it is in the right position right now you can just fix it but when you do that you are completely limiting what you can do with that in the future you can delete the constraints you can select the line select the padlock press Delete and that will remove the constraint it's a cheat but it can be helpful for some scenarios but the create constraint the final one we've got is a symmetry constraint so the symmetry constraint is what it is it makes two objects symmetrical around a centerline so for example we can do let's do a rectangle here and then we'll do a door maybe we're going to have like a sham pad edge it's just truck along and then like that and I will do another section over here truck along like this and I need this line here and then this line here to be symmetrical I want them to be on the same angle whereas right now they're not see that line there's free to change angle so what we can do is create a center line running through the middle of here so we'll draw a line created as a construction line it can be a construction line or a Sun line it's not important but we'll draw a construction line in right click create a constraint symmetry and then what you do is you pick the two objects that you want to be symmetrical and then you pick the center line and it will create that symmetrical constraint those two lines are now symmetrical around that center line and that's again useful for a whole bunch of things not limited to just that scenario there's all kinds of different scenarios you can use these constraints for they are indeed applicable to anything that you can sketch so I am showing some very limited examples here that's the symmetry constraint some of the things which you might find useful let's just get rid of this sketch some of the things that you might find useful is the ability to create a sketch without in vendor automatically applying constraints as you're sketching so for example when I select line and then move it to the horizontal it's probably best that we looks sidon so we actually all get Norah's on a line you can see it's going to be automatically creating a horizontal constraint now if you hold down the control key on the keyboard and keep that held down you can now free sketch without Inventor automatically place and constraints so if you do need to create some kind of bizarre shape and you don't want it to start snapping to the horizontal you can do that in inventor will not made any constraints at all as you're sketching so that's one thing that's nice to know about let's delete that and then let's let's wrap this up let's wrap this up by looking at how to show and hide constraints this button here on the sketch panel bar is called show constraints and what you can do is just select any line and it will show and display the constraints when you press escape it'll keep those glyphs enabled on that object so you can visibly see what constraints are being applied against that line cuz quite often you'll lose track of what constraints you've applied and what's been automatically applied and you need to keep a track of that by visibly seeing the gifts so you can then say right well actually I didn't want those two lines to be parallel with each other so let's get rid of that line and that will now allow us to to be a bit more flexible with how we create the sketch so that's select that button there which is show constraints and then pick the object you can also use keyboard shortcuts of f9 which turns everything off and then f8 which just turns everything on all constraints its f9 and f8 there is more to sketch constraints and that there is a whole bunch of options in here which lets you configure how constraint in Fearon Sande relaxed mode works and various different ways but we're not going to will not go into that in a very basic beginners tutorial so we'll leave it there that's 2d constraints at a very basic introductory level hopefully that is enough to get somebody going with 2d constraints in or a desk in vendor so if you did like that do hit like on the video if you're want you if you want to if you want to stick around hit subscribe for notifications and stuff on future videos and I'll see you in the next one toodles

Channel: Tech3D

Views: 168,432

Keywords: Autodesk, 3D, Inventor, tips, training, guide, modelling, part, assembly, Solidworks, AutoCAD, 2017, Fusion 360, 2D Sketch, Constraints

Id: DWXWrrPHIpA

Length: 26min 6sec (1566 seconds)

Published: Fri Jan 06 2017