The most annoying problem in FreeCAD 0.19 Part Design - Topological Naming [LIVE] (English)

so good evening and hello everybody my name is flowy and i thought i don't want to cut a big video tonight i just thought i want to talk a little bit about a very annoying topic in freecad actually the number one annoying problem that uh hits especially newbies and new users to freecad and i made a big and a very very well video on my german channel about it it's called the topo naming or topological naming problem you should check it let's i don't have the link at hand like topo naming topo naming free cat and you will see in the wiki of free cat it's called the topological naming problem maybe you have heard about it maybe you have not if you have not heard about it yet you it might have even happened to you in the in the past and you should know about it and you should know about techniques to avoid it and you should know about um what to do for a proper workflow not to run into the topo naming problem and if it had and if it happens what you can do about it um you can read this article i'm gonna link it to you the the video description and now i'm gonna show you what is meant with all of this so you don't have to read it so that's what i um prepared it's a very quick model made by me um a few minutes ago and it contains some very nice features like multi-transform features pockets chamfers and pads and i'm gonna show you now how what i did do here so i'm gonna delete the latest feature the pattern and the chamfer so i started with a simple base like a disk then i added the datum plane in the distance from the x y plane in the in the exact distance from the x y plane as the height of my disk is and to achieve this you have to select under the datum plane you have to reference it here under the z direction you have to reference another parameter like pad base dot length so always the length of the pad base is referenced so that the datum plane is always on top of my disk here without attaching it really to the 3d phase that's a recommended workflow and i can show you when i change pad base from four millimeters maybe to 10 millimeters and update my geometry you will see that the datum plane is always on top of my geometry that's what i wanted to achieve here and i need this datum plane to draw my geometry for the pocket for the slot holes here that i prepared here i only drew half of a slot hole in this sketch you see that pretty simple only till the y axis here so that i can mirror it and have a complete slot hole here okay that's what i did and then one of my absolute favorite yeah let's say it's one of my absolute favorite commands in freaka that's the multi-transform feature because with this multi-transform feature with one click i can achieve for example a mirror that makes the half slot hole a complete slot hole the linear pattern in y direction who adds another two slot holes and then finally the polar pattern who even adds five occurrences in polar direction so that we have from a half of a slot hole we suddenly have 15 slot holes in our geometry with one command and until here the whole construction is still fully parametric so whenever i change pads base here again to probably five millimeters everything is going to work very nicely you see that okay then the next thing i did i made a pocket for a circle and i placed a circular pocket here in the spare area between two slot holes that's easily achieved also by a sketch that i placed here like that and i even attached this sketch also on my datum plane that's on the height of my pad so i did not um yes i did not make my sketch really on the 3d um 3d feature not really on this surface here not really on the face but on the datum plane as it is recommended okay and the next thing i did i added a chamfer on the outer edge here of my circular hole so i select this edge i go to a chamfer and after that let's say 0.4 millimeters i have to use the comma in germany i think you americans if you're from america you can use the the point i cannot use the pointer you have to use the comma here but that's just a side note and then i have a chamfer here so and what did i do then i select chamfer and i have to activate another pretty new option that's called the support transform and that support transform makes it possible to only pattern the latest feature like the chamfer and then i will also pattern all of the underlying geometry like the whole pocket is then um patterned okay you will see that in a second i select the chamfer go for polar pattern and i pattern it around the z-axis select the z-axis and five currencies and you would see very nice the polar pattern is now five times around the c axis including the chamfer and the pocket that's exactly what i wanted to achieve and now let's let's come back to the to the topological naming problem what does this have to do with the topological naming problem until now nothing but it will strike in a second and it will strike when i change my pocket here so i go to my pocket circles which is now set to a fixed length or a fixed depth of two millimeters and i change it from two millimeters to through all so i make my circular hole here go through the old geometry i change it and i go to update and you'll realize something funny to happen in a second you see it the circles now go through the whole material but the chamfer here on my circles are gone the chamfer is now switched over to my slot hole that i constructed here and that's because of the internal renaming of geometric features in my 3d geometry so let's i don't know what the exact name is but we can find it we can find it out we can see chamfer if we go to chamfer we see that the chamfer was placed on something called edge 150 and what did happen when i changed the pocket depth here from two millimeters to through all what happened there was that there was a an edge inside of my circular hole here and this circular hole now goes through the whole body so the internal edge here was removed and all edges and all geometric features of my body have changed their names and suddenly edge 150 is no longer this edge here but somehow the outer edge of my slot hole here and that can be really annoying so can we repair it or what's what's the matter so we can go to chamfer double click it and we can see where it is placed we go to edge 150 and then we see a green highlighting here that now the computer thinks it has to be placed on this edge which is complete bs in my opinion so i add another edge this edge and then i can remove the edge 150 which was clearly the wrong edge to place go to ok and hopefully go here spacebar to activate it we have repaired it so that's a topological naming problem in freecad that still occurs i know that some developers are heavily working on it to solve it because in my opinion this is one of the most annoying drawbacks we have in freecad to this moment and um on the website you will find some recommendations here how to avoid it and there are several things you should do or should not do and one thing is not to reference 3d geometry so don't draw your sketches on 3d phases for example don't place your datum planes on 3d phases if possible you have in every part designed body element you have this origin here origin consisting of three main axes the x-axis y-axis and z-axis and you have the three datum planes that are standard in every part design body and whenever it's possible try to put datum planes reference to one of these three datum planes here like for example you can say x z plane new datum plane here and then make it a reference to this one maybe with a c distance here maybe with the um this does not help but no that's also not but around the z axis you can shift it and turn it a little bit so that you can try to only reference these features or 2d features but never if possible 3d features but my point is that for some um features like the dress up features here like the fillets like the chamfers it's not possible to to um reference these on 2d geometry and not on the this datum plane geometry you have to do whenever you want to do a fillet whenever you want to do a chamfer or a a thickness you always have to select a 3d geometry so in this case like this chamfer you couldn't you couldn't avoid it by doing anything different so i think it was important to to show you what can happen what is the topological naming problem my advice is to read carefully about it and to try to make your models as stable as possible i think it's necessary to talk about because i see many youtube videos where the the the teachers don't care about it maybe they don't know about it or they just don't care about it and they just do wild things like in the sketcher what can you do you can draw on on planar faces selecting it and then sketching on it you can reference 3d edges with this command here the create edge links to external geometry you can of course link 3d corners but that will also be very very um danger in danger for the um for the topological naming problem so if you have any questions to it just ask me in the comments under the video i didn't want to make a big video and big fuss about it and cut it and i just wanted to try out if the live stream is a nice thing for you give me your opinion i hope you had a little bit of fun and learned something and have a good time i don't know what time it is here where you are at the moment i'm in germany it's 7 p.m and i'm gonna enjoy my evening now have a good time everybody goodbye flowy is out

Channel: Free CAD Academy

Views: 53,243

Keywords: freecad, free cad, toponaming, topological naming, flowwie, cad, cad tutorial, cad live, freecad wiki, freecad problem, flowwies corner

Id: GKn5kAYmfQE

Length: 13min 17sec (797 seconds)

Published: Mon Nov 02 2020