ZBrush making seamless cuts in your model for 3D Print

hello everyone so i was uh i've posted this model online uh onto several different uh forums and facebook and i've had a couple of people ask how i go about splitting this model up for 3d print because i printed this model this is the print just here it looks super cool i'm really happy with how it came out um this was done on the lego mars resin printer and for all of the pain that you've got to go through with resin and ipa alcohol i know this water soluble but um you know for all of the smelliness and horribleness and dangerousness of that stuff it's worth it for these prints they look absolutely amazing but uh what i'm talking about today in this video is uh how i go about splitting these models up so what i've got is i've got on the bottom of the head here i've got a key and that goes into a negative key here and they fit just perfectly um so what i want to do is just show you my process for doing this there are other tutorials out there that show how this is done but i figured as seeing as there's a million ways to do things in zbrush in infinite combinations i'll show you my method and then you know hopefully you'll learn something from it so well what i need first is the key itself i i i made one just before we started this video but i'll show you quickly how it's done it's actually really easy so if i just take go to any model here uh i'll go to the conditioners oh this one's not a poly mesh so i'll go make polymesh3d oh what am i doing make almost what's in my mind okay and then what i do is i go to initialize and set these down to one and click on q cube and there we go we've got a cube i'm going to go into polygroup mode and what i'm going to do is i'm going to use the z modeler brush i'm going to shrink the top of this a little bit so that you get that kind of you know that kind of tapered thing because you want it to taper in so it's easier for it to click together obviously so what i'm going to do is go to q master i'm going to so i'm in z model here i'm going to scale a single poly on the top polygon i'm just going to scale that in oops if i go in the right direction i'll do that a bit more there we go so we now have our tapered cube shape i don't know what the shape's called well figure it out later um i'm going to poly group that together press ctrl w to do that and then what i'm going to do is i'm going to do qmesh and i'm going to just do all polygons for now but i could do poly poly group all if i wanted to i'll do just do all polygons it's the only thing i've got and what i'm going to do is i'm just going to scale this up so i'm going to use qmesh i'm going to click i'm going to drag but then i'm going to hold down the control key and it's going to be difficult to see what that actually does but with cue you know with qmesh what it does normally is that it extrudes but when you hold down the control key it it creates a new surface i think this is best shown by splitting this up so i'm going to go to sub tool split group split and i'm in solo mode here if i move up and down the tools you can see one is smaller than the other one so the green one is smaller than the purple one and in fact if i turn on transparency turn off high frame mode uh and turn off solo there you go you can see you can see the the line around the side here now what what what you have to think about is what scale is this cube going to be at you know if this was going to be at this scale you would get a lot of slop um a lot of movement between the two keys but seeing as this is going to be about this scale maybe that's going to be okay uh i'm paranoid so i'm just going to i'm going to increase the size of this slightly there we go okay the bottom of the shape doesn't necessarily the two bottoms of the shapes don't necessarily need to be in the same plane i usually apply this key and then dig it into the mesh a little bit anyway move it inside the mesh so but if you wanted to you know you could you could easily uh you could easily move the bottom of the mesh down a little bit just bear in mind that when you do that you're changing the shape it will you know as you're moving the bottom of the mesh down it changes the angles of the sides so i tend to keep that where it is just so it's snug because what's going to happen is as i insert this into the mesh itself i'm sinking it in a bit anyway so it doesn't matter that the bottoms aren't aligned um so yes this is a 4.1 uh there are others you can make quite easily so you can make cones you can you can easily make in fact let me show you what the one that i've made this is actually a really old one um this is this is one that i made a long time ago and i think in fact i think i made these before z modeler was in zbrush so these were probably made using dynamesh and that's in fact these were you created using dynamesh which is why they're decimated but uh i've got like uh four different five different kinds here so i've got the one we've just made um this these also have slight curves on the corners but also made the cylinder version which i was talking about earlier i've got a cylinder here with a key on it so if i draw that out you can see it's got a little key so when that turns into a negative the inner one will slot inside and it will just stop the model from rotating so it can only go in at one orientation i've got that on here uh on his arm his robot arm he's got so that's what that's used for so that keeps the arm in the right place i'm gonna break this model i've dropped it so many times now right there's that one um then there's this one which is a little bit harder to explain but effectively uh if i auto groups all of this i hide away the outer one there you go so the inner piece is this clip and this slides inside the negative space and you can see the negative space is like a complete cylinder with that little catch at the top so the idea being is that this slides in with no glue clips together and then you can rotate it round so it it's a toy movement and there's another version of that let's go back to here uh which is slightly different and what this one does uh it's the same thing but you can see it's got flat sides and so if i auto group that and then hide the outer layer it's the same pin inside but the outer has got that flat edge on it so again this is just something that i can just clip together doesn't require any glue but it doesn't rotate the only thing with that is that it goes one of two ways so i was thinking about making one that can only go one way but i haven't done it yet okay so you can model all these with z model quite easily but you must always have an inner version which is slightly smaller than the outer version so the outer version is going to be used to make the negative space the inner version is going to be used to actually make the key all righty so now i've got those let's flip back to my model uh transparency go back to solo okay so let's say then i want to start splitting this guy up um and i'm gonna make a really sloppy job at this now because you know recording this is a video rather than actually doing this in real life so that means that this is going to be rushed but what i would do is i would actually slice this thing using the slice brush so i've got a quick menu here with all my favorite brushes on it so this is a slice curve and i absolutely love this brush it's really really useful so what we're going to do is we're going to go into polyframe my shortcut for that shift f i think that's standard but as you can see i've got a custom ui here it's just more efficient and i encourage anybody to get a custom ui if once you've been using the app for a little while get your favorite tools in the right place get some menus set up like this you know tons of information online on how to do that i might make a video on it one day but let's not deal with that now okay so what we want to do is we want to slice this arm up and um i would like ideally for the arm to be seamed along the cuff of his shirt so that when they slice together when they slice together when you stick them together like this you can see that the thing is seamless right and the reason it's seamless is because the arm goes slightly inside the shirt there but when this is glued together it will just look like one model it won't you won't tell where the seam is so that's the goal now this is a bit more complicated for this model because this is being pre-decimated it was a mistake i made where i got to this stage i decimated the model decimating let me show you the lines but basically you can see here all these triangles so this has been through a process in here which is called decimating the model um for those who don't know this model when before it was decimated was i think about 13 million polygons which actually isn't bad considering the amount of detail that's on this thing but then i've merged it all together and i decimated it and now it's not polygon sorry points it's now um this particular sub tool is less than 671 000 well less than it's 671 000 points which is really really cool and actually once you've decimated it um because of the size this thing's going to get printed at you are not going to be able to tell any difference in detail and so that's why i decimated it but if i'd thought about it i would have done that after i had split the model up because apart from anything once you split the model up those tools i tend to budget myself up to a million points just because it allows my printer to have a fine chance of loading the model so if i budgeted myself a thousand a million points for each object that i'm going to print then i can get some good detail on those but i digress let's uh so again this is going to be a rush job but you know what we've got our slice tool selected and the very first thing i'm going to do is i'm going to make a rough cut okay and this rough cut is i'm holding down control shift to get the slice tool out i'm tapping the alt key which lets me uh move this thing around now you can see i'm at this point here where it's like clicking around and the reason why is because as as default if i'm holding down control and shift this thing's going to move in five five degree increments but if i release the shift key keep hold of the control key it now moves in just one degree increments okay so i can get this into more or less the place where i want it to be and also if i hold down the spacebar i can move this thing around you know i kind of do this without thinking now which is great it means i can really get in at the right angle so i'm just going to come in here like so i'm tapping the old key i've just realized i'm going to get a piece of his ear but never mind okay and then i lift the stylus off okay so that's cool and what i'm going to do is i'm going to ctrl shift and i believe i can hide this part of the mesh that's great and in fact let's go back to select and hold on control shift and alt to hide that part away okay and zoom in a bit here and then i'm gonna go back to slice curve and this time i'm coming top down so it faces the other way again move it around a little bit tap it alt tap it alt move this until i'm happy with it again and move that up cool and then hold down ctrl shift alt and tap and that gets rid of that bit and then there's another bit over here go up this time so it faces in that way so i just want to make sure i'm not including his uh bandage and his arm all right release ctrl shift alt click all right now again you know if this wasn't a tutorial i'd spend a lot more time doing this and really get the model into a shape where i'm happy in fact if i uh oops go back to select uh what you'll see here is i've got all this bit here so i'd spend time getting that in as well but let's just say you know what we're happy okay in fact this bit is going to cause a problem for the tutorial so i'm just going to grab this right now let's go back to here oops again holding down the space key lets you move this around [Music] as well that okay that's probably going to do is the least amount of damage right okay i'm going to press ctrl w to polygroup that thing all back together again and you can see by the way um i'm missing a little piece up here so i'm just going to reverse this mask there it is put that back there okay houses here cool and then probably do that reverse okay quick so now i think we're going to split the model as i want as again you know i'd spend more time on it but now i've polygroup these things up what i'm going to do is i'm going to actually split these by groups and you know it's important this is why i try and make everything the same polygroup for each of the parts um and i can do split in many different ways i can do split hidden in fact i'm going to do split hidden um okay so what i've now got is his arm separate but he's got a hole in it which is not helpful so there are several ways i could fix the hole um i could do all sorts of union i could use um balling mesh to do this in this case all i'm going to do is close holes because it's a more or less flat surface but whatever um close ups and you can see there that this has given us some sharp edges so i'm going to deal with that i'm going to go up to this one here i'm going to do the same thing i'm going to do close holes close holes where is close holes uh close holes is in geometry uh modified topology close holes okay i have it again on my custom menu because i'm posh i'm not really worried about this mesh i'm going to leave this mesh as is but this one i've got some maintenance to do so here's what i'm going to do i am going to first of all deal with some of these islands that i've got you know again if this was um if this was if i had more time those islands wouldn't be there okay so what i'm going to do i'm going to do this this way yeah i'm going to go to my move tool alt click on this control click on this because control click if you control click on the polygroup it masks all the other polygroups uh and then i'm just going to move this up like that a bit more and then i'm going to shrink this down like that okay that's cool uh here's what i'm gonna do hold down and move this up and move it up again and shrink this down a bit there we go so i've just made some poly loops by holding down control and i'm going to go to a brush i'm going to press the shift key to just smooth this out okay okay so i'm just smoothing out the edge a little bit here um because what you want you do want this to be tapered but you also it needs to be fairly smooth so ignoring those artifacts that i mentioned you can see now what we've got is an arm and it's indented slightly because i've moved that surface out and i've smooth around the edges so it's tapered properly okay the next thing i'm going to do by the way these artifacts that you see here don't worry about them they're going to get dealt with layer if you do this as long as they're subtle and these ones are they're actually i think inside the cuff they're going to get dealt with so don't worry about them in fact they'll get dealt with in the very next step so what i'm going to do is i'm going to go to my brush i'm going to load up my insert mesh yeah you know let's use the one that we made earlier on and i'm going to orient this and then i'm going to draw my mesh out and it's masked the rest of the mesh which is really useful because what we're going to do is we're going to move this until it's in there it doesn't need to be much you know you don't need to have the mesh you know out here somewhere or anything like that it really this this is probably just more than enough uh okay so there's that and what i'm gonna do is go to here if i ctrl shift click you can see it hid the whole thing so what's happened is is that the insert mesh brush that was created was actually created all under one polygroup so what i need to do is auto group that together so again i'm going to use my auto groups feature okay and you remember those artifacts that we were talking about earlier on that are there okay we're not going to worry about those so here we go so i'm going to do this merge that ctrl shift alt okay that's all gone all right and then reverse this i think actually well let's delete hidden okay i'm just going to check something here yeah okay so what we're gonna do it for some reason that polycube that i made before didn't work so let's use the brushes i used before i will put these brushes on gumroad as well you don't have to pay for them you just download them um but they work i think there's already three print brushes on there but they're probably better than this but whatever you can take these ones for free i'm happy with that all right let me go get those here we go 3d print keys i'm going to use the square one here we go draw this out too big there we go and again i'm going to move these in i mean even though i'm offering those keys for free i do encourage you to make your own because it's a good learning process i'm not sure why that didn't work i know why they didn't work it's because they weren't all one polygroup i bet that's what it was anyway so there's our key that's in there now and here's where things get interesting what i'm going to do is i'm actually going to go to my sub tool yeah i'm going to rename this to arm i'm going to duplicate that i'm going to rename this to um cutter okay so let's deal with these one at a time arm is going to be the model that is going to get printed and at the minute it's using the um the cavity thing on the outside so we want to get rid of that so what i'm going to do is i'm going to auto groups again okay i'm going to hide the outer one and there we go so now if i flip between arm and arm cutter you can see that that i keep calling it a cube i can't remember what the name of the shape is that tapered cube is as you can see it shrinks on the arm on the arm model that is slightly bigger on the arm cutter model which is important right so the arm one now i want to make this all one mesh so what we do is i'm gonna uh i'll just poly group this all together and then i'm gonna go to my gizmo i'm going to do remesh by union okay let's do delete hidden first can't do this when you've got a mesh partly hidden um okay cool so you see where this is happening um i know what to do with that so let's go back to our brush and if you get a message like that which basically says not valid first of all close holes second of all you know let's do this here first of all i go to geometry uh i go to [Music] modify topology and then go to close holes i then go to mesh integrity which is in the geometry menu and i do fix mesh don't even bother doing check mesh uh i do close holes fix mesh oh i do one more thing modify topology which is optimized points um so the first one fixed mesh there's some weird artifacting that can happen in your mesh where two points share the same space and that confuses the union tool the second problem that can happen is that you get holes in your mesh and they're not watertight if that happens just do close holes and that helps um that's not the same as having a 3d mesh that's got like a pocket inside of it that's not what this will fix what it fixes where you've got a break in the topology and there's an actual physical hole in the mesh and so this doesn't know what to do with that and then the last thing optimize points when i do the fixed points and i do the closed holes sometimes what you'll end up with are islands inside of the mesh they're not used for anything they're just floating there so i do optimize points because what that will do is it will just remove those floating islands on their own and i'll do that again after i do the union so let's let's get on with that so union remesh by union ta-da now it works and also it didn't give me any errors as well sometimes what will happen is it will say it worked but it it gave warnings which is fine all that means is that a part of the mesh that's union together has broken off and is now floating on its own and generally speaking that's usually inside the mesh so it's not normally a problem but we've got some cleanup to do after this so the first thing i'll do is click on the cog and click accept so we now have our new mesh but as i said i want to do that clean up and it's the same process i just did which is close holes fix mesh and then optimize points the next thing i do with this although optimized points is great sometimes those little floating islands are outside of the mesh rather than inside so what i'll do is i'll go auto groups and then i will ctrl shift click as long as i've got select rectangle selected control shift click on the main mesh go back to my menu and i'll i'll do uh if you're split hidden it is enabled that means you've hidden some little artifacts somewhere so i'll do delete so now what you've got is a printable mesh right so that's all good i know it's a lot of steps but re-watch the video and you'll you'll get used to it again i don't really even think about it i've done it so many times with this model now i just kind of do it but this is effectively good to go okay so that's that so now what we've got is because we've got our arm ready to go what we're gonna now do is use our cutter uh right the cutter is going to be used to cut out of this pile okay so if i scroll up you can see there they are i've been very careful to try and not move these in 3d space because if you start moving things around of course it's not going to work but what i need to do first of all is rename this to the name body you can name it whatever you want but this just helps me and i'm going to move that above arm cutter because when you merge the tool that's on top is what the new sub tool will be called okay um it seems weird because you're merging down and so i would expect what you're measuring down into to be the name of the new sub tool not the case okay so what we've got is our arm cutter and in fact if i just move arm underneath that i try to keep the tools i'm working on at the top just in fact at this point i might actually make a new folder and put the subtool in there and call that complete um but again you know one thing i like to double check here is that i've definitely got the right key before i do the cut so there's the arm there's the cutter arm arm cutter and you can see the cube is growing on arm cutter which means that we're good we're golden so now what i need to do is go through the same process again of um doing a rematch by union so i'm just going to poly group that all together you don't have to do that by the way let me show you what happens if you don't do that and uh yeah so first of all let's let's just bake close holes fix mesh and optimize points and then go to my move tool remesh by union uh accept and then i'll just merge that all together and then i'll go to my menu close holes fix mesh and optimize points and then the next thing i always do just because if you've got any of those floaters and they're floating where the keys are they can damage the mess you're trying to cut from so i don't want to do that so what i'm going to do now is auto group with my select tool drop shift click on there i've got split hidden enabled so i need to do delete hidden and that's got rid of the artifacts floating around in space finally we get into the step where i will now merge this down now if i merge this tool down this tool i'll lose the history on but this tool will become the name of the new subtool okay so let's do that anyway merge down i'm going to use my menu to do this because i'm going to remember it's in the merge here actually merge down okay there you go you see so the new software is now called merge body but the new sub tool has the history oh no sorry no it does have the history of the thing immersion down for good okay i stand corrected happy to be done so right so here we go oh by the way if you noticed uh there's a little artifact just here don't worry i cleaned that up later after i found it this meshes way back in time all right so now we've got our whoops now we've got our two points here on two different meshes you can see that that is going to seamlessly fit in here um and it's also underneath the shirt here and again you know if i had more time this wouldn't be a thing it would all be lining up the shirt which is in fact what i did with this guy you know it fitted enough battle what i now need to do is make this a cut into this and the way you do this is i'm going to hide everything apart from the cutter i'm going to go to my polygroups menu i don't have this on my custom menu yet which i will do but uh i'm going to do this as uh group as dynamesh sub and you can see it goes white so what that now means is that this is now a negative mesh it's not a reverse mesh it's a negative mesh that is going to be used to cut away from the other meshes that it touches when i do a remesh by union or dynamesh so i'm going to do remesh by union though because you know what i'd like to do so let's bring the whole body back and this is where hopefully the magic will happen and all that work we've just done and again you know i'm talking about this so this would take me literally five minutes to do more apart from selecting the right mesh okay so let's go to move move uh remesh by union got a little music going in my head now okay this is the thing i was talking about earlier so it says the boolean operation has succeeded but several warnings excuse me were reported during this process the resulting subtitle may or may not contain a few inaccuracies may or may not love it again what that normally means is that it's created some floaters we'll deal with those but as you can see now what's happened is that it's cut the hole in the mesh so that's now made this negative space for the arm to fit into so we're going to do our process here i'm just going to first of all auto groups this auto group i'm going to close holes fix mesh this takes a little bit longer because this is a much more complicated mesh he's got much more points optimize points and then ctrl shift click make sure select rectangle selected click on the mesh there you go split hidden's enabled so that means that we've just hidden some artifacts delete hidden and anything that that warning was talking about has now gone this is now an almost printable mesh there's still bits i've split off but this is our mesh and now if i go out of solo mode there you go so what you can see now if i go to the arm here and move and i move this away there we have it we now have our mesh and a negative space for it to go into so there are some artifacts around here and that's again just because i was doing this for the video i was doing it quickly but this is a really powerful method and um i'm not the one that came up with it this is uh various different tutorials online i've put i've just taken the best bits of and use this in my own workflow um but it does mean that i can just clip this thing together i get no seams on it but it registers nicely in the right place because of these keys and as i said i am going to put these keys that i created online uh i'll probably put them in gumroad and once i've done so i'll put a link in the description of this video um but that's it folks you know this is now you know imagine i've done that with the with the rest of the model this this model would now be ready to print that's it so i hope you've enjoyed the video i'll speak to you soon is btc i might never see you unless you're in my house in which case that's weird see ya

Channel: Mark Johnson

Views: 13,269

Rating: 4.9175258 out of 5

Keywords: 3D Print, ZBrush

Id: mH81IbjF4so

Length: 39min 22sec (2362 seconds)

Published: Thu Jul 02 2020