FreeCAD: Sketcher - Offset / Outline Geometry and Problems and Fixes Converting to a Sketch

so we're going to look at the ways of outlining and offsetting sketches and the problems that you may come into and how to solve those problems we're going to start in the sketcher and i'm going to create first of all a closed non b spline shape to do that i'm going to create a new sketch and i'm just going to use the x y plane for the time being in here i'm going to create some standard geometry so we're going to have a couple slots and i may place let's get that and may place some trims in here so i'm going to bring this over and trim out these two so these are standard geometry we're going to keep away from the b-spline for a moment we're going to come to that in a minute and let's say let's place a box down here something like this not worried about constraints i was there constraining it then you'll be here for quite a long time where i start constraining this down to be fully constrained so i'm just going to trim this down it's trimming away geometry so it's all part of one geometry now we're just gonna get rid of these bits inside so i've got this shape here and i want to create the same shape and outline against this well it's going to take me a while to actually sketch inside this and there is outline tools available and we've got this shape here so how do i outline this well go to sketch you can see we've got tools here but we can't see anything within here we've got copy clone symmetrical move etc etc the tool that you want is over in a different workbench so it's actually over in the part workbench and it's this tool here it's the utility to offset planner shapes it can come in it may actually be when you come into the part you may just see this icon here but it's also available in part 2d and 3d offset now to use it we select our sketch and we come in to part 2d offset and you can see we've got an outline that's happening here so we can send it outwards i'm going to send out 1 by 6 and we'll create this outline that goes around here see some of these edges are curved here and that's because we got this arc on so it's a tangent that actually set those sharp edges there which has been done by the square as a tangent so a tangent means touching and those will be touching there also we've got intersection which means they'll take this line and this line and grow them until they meet and of course you won't see any difference with a square because those lines do intersect like so there's other modes here which are more related to as you can see there's an error come up here more related to the objects in the part rather than the objects in sketching we can send it inwards as well but we have to be careful here from the minus six send this inwards you can see the intersection working here they are growing to meet and if we send it to tangent well they're touching anyway way arc it's just rounded that off there you can see where it's rounded that off but if we do this too far then we start to get breaks so for instance if i did 16 26 this geometry is not actually doing that at the moment this geometry may start to break you can see we've got problems here that it's actually broken into two here and if i did tangent or intersection there you can see we've got problems skin there's even more problems there so let's just change that back to pipe and change it to arc so let's be careful when we go in was when it gets to going inwards this far then we're changing the actual properties of the geometry anyway we're changing its shape it's gone into a different form here so if you're looking to grow inwards then it might be best to do a smaller shape and then grow that outwards from there we've also got fill offset which actually fills that as a face if i roll over it you can see two down the bottom is saying offset 2d dot face one so that creates a face there and we can okay that to actually get the face on there i'm just gonna set this something like six going outwards and i'm gonna use the tangent because i want to maintain the squareness of these lines down the bottom click ok now say if i wanted to edit these lines that got run around the outside how would i do that well to do that we need to come over to the draft workbench now on the draft workbench you will also see a tool for an offset in here which is this one here offset selected object so you've got that one there but it works in different way the two different totally two different tools there we'll have a look at that one in a moment one that i want to look at is this one here convert by direction between draft objects and sketches also available on modifications and draft sketch so we've got our 2d offset and what we're going to do is actually take that offset that 2d offset and convert it into a sketch so we can edit it to go out to modifications and draft sketch we get this sketch here double click on it you can see now we've got a sketch that we can edit obviously our constraints won't come across because we've got converted to an offset and then we're converting back to a sketch we've got a nice sketch there that we can edit we still got parts of this coming through and that's because we haven't actually come in and hidden that offset so i can modify that add constraints to it etc etc let's look how to actually combine that sketch with the other one so i'm going to come out here click close and come into this offset which i've just hidden by pressing the spacebar and click on the sketch i'm going to use the control click on the other sketch but first of all i must come down to the sketcher and there's an option on here called merge sketches it's greyed out at the moment because we haven't got two sketches selected so select the sketch select the other sketch and come out to sketch and merge sketches it won't remove those two sketches what they'll actually do is create a new sketch there and we've got these two that has been created from we can get rid of this offset we can get rid of the original sketch and the other sketch because this has no reliance on the other two sketches and now if i double click on it we have got an offset in here of that sketch our original sketch and offset from that sketch fully editable we can constrain it and do what we like with that this is also possible with single open sketches and when i say single open sketches i'm going to click on that one press spacebar just get rid of it i'm just going to create a sketch in here xy plane okay and we're going to create a arc so i'm going to go from here to here and create a simple arc like so so that's an open sketch it's not closed it's not coming around to here and closing up it's an open sketch and we can come into the path again and create an offset against that this one here utility torso bring this down to the offset and something like 10 again we can use the minus to go inwards so minus two you can see that's going inwards then go down here click okay we've got those two offset there we can use those with extrudes if we so desire and okay that's saying no shape selected so we've got select the shape and we've got our offset we can select and control select the other shape as well hit okay and those will offset like so so we've got two shapes that have been offsetted against each other probably seen the 3d one in there we click on that and you got you got a 3d offset there and we can offset that and so it's saying that 50 10 and fill the offset and that's filled that offset against those two and made an arc so we've got 2d and 3d against those two but we're just looking at the 2d offset at the moment so let's get rid of our screws that's strewed yep let's get rid of that and that offset and bring back those two sketches well that's single sketch and the original which is there double click the offset and we can modify this if we so desire and we've got those there so let's offset both of those there again you can convert this over in the draft workbench and convert that one to a sketch and we double click on that and you can see we've got our editable arc there close that those will run with the geometry in the sketcher so slots polygons squares polyline etc when we come to the b spline it's a different matter and problems can occur with that one if you want to edit it so doing the offset and all that is absolutely fine we can offset that no problems at all when we come to converting it by direction between sketch and the actual wire there then things tend to break down and i can demonstrate that so i'm going to get rid of all these and create a sketch and x y plane and we're going to do a b spline like so b spines can be problematic not just in free cad but in alpha cab programs as well because they're quite mathematical intense so we've got our b spline and again we can come over to the part and we can do the offset against there so the 2d offset so absolutely fine you can see we've got breakdown at the top so let's change this to tangent we've got problems here change it to skin you can see we start getting into issues and let's just set that to 1 and change it back to arc back to pipe and it's this point here you can see because it's quite a straight there and we're starting straight away you can see the problems that we're having in that no matter what we try we have issues there so i can close this if i so desire with other tools if i hit okay and i wanted to close that then i would use something like the curse workbench which has a number of tools in here the curves the stand and the join curves etc etc and i can come in and close these so i can take these two here and i could even use a blend a blend tool against those blend curves between two edges this workbench by the way is not available as default with freecad you have to install it so you just use the tools add-on manager and install it from there it's called curves workbench and you can store it from there so there you can see i've created an edge there by using the blend curve and in the blend curve there's continuity so for instance if i want it straight i can use the c0 and kind of two new t on this side is c0 and you can see i've created a straight line across there and we can affect that from the scaling changing the continuity and other factors in here i go into this in another tutorial my curves workbench series which is coming up quite shortly actually i'm going to be using the curves the blend curves in there and going through tutorial on that because it's quite useful tool but the the continuity there is the continuity on this edge and this edge so it's the connection between these edges and we can repair things like this and then take these and combine them together so upgrade them so i can go into the drafts workbench and after i've fixed that those two there take these tool and use the upgrade on there if i'm not happy with the size of this i can come into the offset and just increase this size so let's crease it by five like so hit okay you can see that we need to sort the blend tool as well because that's disappeared and just delete that blend tool come back into the curves workbench and then click one click the other and just use the blend curve between two edges there and come down change the continuity always start from c0 and looking up the other edge z zero so we've got that straight now and then we can change these to something like g1 and then change the scaling the scale factor and what will happen is you can move that into position like so and just play with the curve between those to actually fix that like so so we've got a nice bit of distance between those two so what do we do how do we get this to a sketch well we need to come into the draft workbench and we need to combine these together so we take these two first of all come up to the upgrade and downgrade which upgrades selected objects into a more complex shape also available modifications operate you see we've got a single wire now it's got rid of our original curve and the offset is still there which is there but we've just upgraded that there so we've got that there and then we can convert that come in here convert by direction between draft objects and sketches so we can use that there and sometimes this will work and sometimes it won't as you can see it hasn't worked here and it hasn't created a sketch for us we've got nothing in this sketch and we did have an error that come up so we have to be wary of this that if we're using b splines we actually approach certain problems sometimes these can be fixed and the curse workbench allows you to fix these so if we go into closing that and coming back into the curse workbench we're going to work on this wire so we convert it to a wire we could actually bring this back out go back to the offset and the join curve sorry the blend curve there and sort those out but i've gone back to the wire i'm going to click on that sketch which which actually fails just gonna get rid of that and i'm gonna come in and click on this sketch the internal sketch which is inside the offset press the spacebar and make that invisible so we've got this wire now and i'm going to use the join curve against that so we've joined that into one single curve like so if i try to convert this to a sketch coming over to the draft and then convert to a sketch go in that we've actually got further we've actually got the sketch in there but you can see the control points is just a single point here which you know i'm trying to move this i can move it this way i can't move that control point because we've got problems there let's close that and get rid of that join curve so we've still got the sketch sitting there let's get rid of that and we want the original wire that's what we originally want so we've got this wire here let's go back to the curse workbench and let's explore a bit further so we tried doing that and the join curve kind of worked let's try the split curve now so what's happened there is that it split it and we've got the vertex is preserved from that wire jump over the draft workbench and see what happens this time so click on the split curve come in and convert by directionally between drafts and sketches again we get a problem so straight away we've got this problem and come in we've got nothing in there so we've again we've hit an issue so you can see how hard it is to just get rid of that split curve to convert b spline objects two sketches when they've been offset and it doesn't convert it into a b spline that free cad can deal with with all the control points etc on there we can get so far by coming into the curves workbench and then using that wire and converting it to join curves and then using that join curve by clicking on the actual screen and converting it back into a split curve so we've got a vertex there now sometimes this can make a difference so i can click on the split curve and convert it to a sketch we didn't have any errors come up and we look at it and we've now got this point here which we move it out you can see he's still got problems with it but we have some editable ability with this we can move it and we can move this what we still have some problems even if we come in and let's just get rid of that sketch come into the split and increased the values let's add a few more in here something like 23 50 and 75 so those will create vertices around there and actually split that curve into additional edges so we've got that there i've got our draft convert it to a sketch and we've got some more vertices to play with but we still haven't got the same thing as what we had when we had the original sketch got more pliability over it but the original sketch come back to the original sketch you can see we've got these nice node manipulators here to manipulate the curvature this is all to do with that whole conversion back to a b-spline and you'll find this with svgs in boiling svgs you'll have these curves in there and trying to manipulate those curves sometimes it's just best to retrace those but if you're not looking to come up back to a sketch and you just want to do that offset then that is sufficient enough with the b-spline and also you've got the curse workbench tools to repair gaps in here if you so desire but that's up to you if you want to use those looking at the other tools to offset we're going to go back to a normal sketch so i'm just going to create a normal sketch it's going to kill that offset let's get rid of that and let's create a sketch again some simple geometry x y plane okay that and we'll just create something simple again with a trim in between so it's not exactly the same geometry trim those two out of the way those there so we've got this shape here so we looked at the offset in the parts by clicking on the sketch and using the offset there and sending it outwards or inwards so we got that one there let's cancel that also got the draft offset which you saw is very similar icon there and we click the sketch and we can try to offset this outwards and that has some interesting effects as you can see we've got some broken lines here that have over lapped each other so sometimes you know it this one this one could be used in the drafting but when it comes to stuff like sketching then that tends to break down let's get rid of that also it's not very good with the b splines of either it tends to not work at all on the b splines if we get rid of these and just come back to something like a plane so there we go this plane here let's give it some dimension so like 50. and create that plane so create that plane here we still got the gridding showing from the draft let's go into the draft and get rid of that grid there we go so i've got this plane here back in the part and we can use a 2d offset against our plane so this 2d offset here you can see what's happened there and if i increase this offset you can see it increasing so this offsets faces as well so we've got a plane there and we've offset the face it may look a bit weird because our original plane is lying over the top of here and again we've got the tangent to make sure those are square also the intersection which is going to be anyway because these will follow this way and connect up and we've got the skin and the pipe we can send it minus value as well okay that and inside here obviously the plane doesn't disappear you can see we've gone inwards there now we can change that offset if we so desire so i'm gonna go outwards and we'll have the arcs around the side there like so so there's a 2d plane with an offset there so you can actually grow your shapes in there so another thing i want to show you is that in the part workbench if we create shapes in there or shapes from anywhere we can actually use the offset from there as well so i'm going to create this box here and i'm going to extract some of these faces so i want a couple of these faces off here so i want two faces that sit together so say these two or these two so i'm going to stretch out those two faces i'm going to use the curse workbench games for this i'm going to click on those two faces and use the stratos subshape so i've pulled out box face four and box face one so the two faces there what we can also do if you don't want to use the curves workbench we can come over to the draft and if i just delete these and bring back the cube by pressing spacebar to hide or show the cube in this case showing it we can click on the cube and use the upgrade or downgrade so i'm going to downgrade this now downgrade it into a number of faces so you can see these faces here and we can select which ones we want to keep and which ones we want to delete etc so i'm just deleting those faces from there i've got another one around this side as well they've got the two faces there and we can actually use these faces with the offset and come back to the part and click on the two faces and you can see that the utility offset the actual shapes is not available it's grayed out you have to make these a compound so you have to join them together and that can be done by part compound and make compound or there's a little icon here that says compound tools click on that and that will compound that object together that means if i click on it you can see those two faces there you can see the offset has been made available click on that and we can get the offset here we also send it inwards like so and further and okay that so we've got that offset and that original face in there so you can see that compound is sitting there and we can do operations on here so compound is sitting there and the offset is sitting there so we can select the compound control set the offset and do such things as make cut and we can create like a frame that goes around there quite easily so you can see the offset tool is quite useful for a number of different operations not just for sketches also in the part as well if you like what you're seeing please 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Channel: MangoJelly Solutions

Views: 3,695

Keywords: CAD, three, 3D, CNC, Printing, solidworks, autoCAD, outline, skin, offset, sketch, sketching, free CAD, 0.19, 0.20

Id: VRGBU7eQS3Q

Length: 29min 55sec (1795 seconds)

Published: Sun Oct 03 2021