Blender - Connecting Cylinders - #15 Subdivision Surface Modelling in Blender

okay so our chess set is looking great but before we make the queen i want to talk about joining curved surfaces now at first glance it looks like booleans are the only way to create some of the more complex shapes but that just couldn't be further from the truth in fact a boolean will destroy your topology instantly with zero chance of recovery you can spend hours moving in merging points on an unfeasibly dense mesh but at best you're just going to disguise the problems you created when you decide to use a boolean the shape doesn't just have bad topology it really doesn't have any topology at all let's look at a simple example where we want two cylinders or pipes connected to each other let's delete the default cube and press shift net to bring up the add menu and add a mesh cylinder i'm just going to turn off the end caps we don't need them for this demonstration and in fact that just makes things worse we're about to destroy it anyway with booleans but do check out my video about cylinders if you want to know how to create one properly now i'll just tab the edit mode scale it in z by a factor of two just by pressing s z and then typing two and hitting enter now i'm going to tab back to object mode and make a copy of this sound up by pressing shift and d and then rotate it in y by 90 degrees so r y 90 and enter then i'm just going to move it along the y axis a bit so we have these two shapes but we want them to be one object and it seems difficult so people normally resort to the boolean modifier so we add one and select the other object in this drop down box change it to union and let's just apply it and delete the other cylinder so we can see what we've got now if we tab to edit mode we can see well it's awful in fact it's much worse than it even looks end guns and triangles everywhere it works as a flat ended model and that's about just where it's usefulness ends if i say the shed smooth it'll start to reveal its problems i can turn on the auto smooth option for the mesh and uh and then we kind of get back to where we started i suppose everything's a little smooth around the edges but there's an impossibly sharp connection and we can see the edge of every polygon around our mesh to stop that happening we need to start with ridiculously dense geometry in our initial two cylinders we certainly can't add a subdivision surface modifier to this so to this point you'll see people going into the mesh and starting to move and merge points and it takes ages and it's really fiddly work and every time you move or merge a point you're compromising the integrity of the shapes even further with a few hours at it and some interesting applications of weighted and split normals you can end up with a shape with many thousands of vertices which when viewed from a distance will look just about passable but you won't have any control over it you won't be able to use other modeling tools like lattices and deformers it'll always be dangerously close to breaking and there are a hundred other problems which i don't even want to go on near if i had a simple deform modifier too which is a common and powerful modeling tool in its own right we'll see this shape can't even handle that there's a much better way we can delete all of this it's rubbish now let's do it properly if i press shift a to add a mesh cylinder and now in its properties box i'm going to give it 16 vertices that's more than enough it doesn't really matter how many years and i'm going to change the cap fill type again to nothing you don't have to do that it'll work perfectly well with end caps or not i'm just taking them off so you can see more clearly what's happening anyway i'm going to go into edit mode press a to make sure everything's selected press s z and type 2 and hit enter just to make it taller now tab back to object mode press shift d to duplicate it and press r y type 90 and hit enter now just press g to translate it and press y to move it along it doesn't matter where you move it as long as the intersect it can be as deep or as shallow as you want and we'll be able to change that at any time now i'm going to go up here and turn on snapping and i'm going to change it so that things snap to edges again you don't have to do this but for my demonstration it'll just make the placement of the edges a little easier now in edit mode just press ctrl and r to add a loop and after you left click to confirm that you just want one loop right click and that will leave it exactly in the middle now press ctrl r again and add one loop on the right hand side after you left click to confirm that you only want one loop move the mouse so that it's over this vertical edge on the other cylinder and our loop will snap to this position so you can just left click again to confirm it now press control and g to add this loop to a new vertex group we don't want to rename it what we're going to do is we're going to take all of the vertices that make up this group and we're going to shrink wrap them onto the surface of the other cylinder wherever they kind of intersect and later i'll show you we're going to be able to create a loop from this shape if we have two of these loops one for each side on both of the cylinders hopefully it'll make more sense when we get going now press control r again to add a loop at the other side left click to confirm it and again just move the mouse over this edge next to the center edge and it'll jump into place left click once more to confirm it and again press ctrl and g and select assign to new group we're done with this one now so tab back to object mode select the other cylinder and tab into edit mode for this one again just add one loop around the center it doesn't matter if snapping is trying to move it somewhere if you just right click it will go exactly in the middle now add a loop above this one and make sure it's snapped to the first edge above the center on the other cylinder after you left click to confirm the loop again press control and g and make a new vertex group finally do the same for the bottom half of the cylinder press ctrl r left click move the mouse over the correct edge and left click again to confirm press control and g and assign these points to a new vertex group now let's tab back to object mode and it'll be useful for us to be able to see all of the wireframes at this point so i'm going to go up to the overlays drop down menu and just tick the checkbox for wireframes okay now we're going to add some modifiers to do all the hard work for us so go over here and add a shrink wrap modifier we'll change the wrap method to project we're going to change the axis to zed select the target as the other cylinder either with the eyedropper or from the drop down menu box and in vertex group we want to select the first group that we made it'll just be called group and finally we want to change the offset here to minus 0.1 and it's this offset that kind of pushes it away from the other cylinder and whatever you set this value to will define the overall softness of the connecting area so it's worth playing with the offset but minus 0.1 is a good starting point and you'll see now that this top loop here now surrounds the profile of the other cylinder now we want to do the same for the loop at the bottom and we can do that really quickly just by duplicating this modifier delete the vertex group in here so that we can select the other one and because we want the vertices of this loop to be pushed down along the local z-axis we can turn off positive and select negative instead good now we can see that our two loops follow the shape of the other cylinder now we want to do the same to the other cylinder and we could just repeat those steps on the other one or to make things much quicker we can just select the other cylinder in object mode press shift and select the other cylinder and then press control and l to bring up this menu and from here we can tell blender to copy all of the modifiers from the last selected object to the first object we had selected and it doesn't do anything at first because both of the new shrink wrap modifiers on this cylinder have this cylinder itself as their target so we can just press the little x and and select the other cylinder as the target in both of these shrink wrap modifiers hopefully that makes sense now you'll see our two loops jump into position around the other cylinder even better than that we can now select this cylinder and move it back and forth along the y-axis to specify exactly how deep we want the connection to be and you can see our loop's moving to continually surround the other cylinder it's best to find a point where there's kind of an even space all around the edges but it'll work no matter where you place it now i'm just going to put it somewhere around here i can check the other cylinder too but if it looks good on one of them it will be good on both now when you're happy with the placement of both the cylinders you can just press tab to make sure you're in object mode and just apply all of the modifiers on both objects when i can go up here and i can turn off the wireframe display now we don't need that anymore now just select either cylinder and we want to delete all the phases inside the older loops so we can just switch to face select mode by pressing three and go around selecting all of the kind of misshapen faces once they're all selected press x and choose faces and they're gone tab back to object mode select the other cylinder tab into edit mode and do the same on this one go around selecting all the phases inside and then finally press delete and choose faces now we have these two separate objects and we can very simply turn them into one object by pressing ctrl j when they're both selected in object mode they're now one object and if we tab into edit mode and switch to edge select mode we can alt and click any of the exposed edges inside the shape to select the entire closed loop that surrounds the cut on that side hold down shift and alt click on any edge on the other side of the gap and both full loops will now be selected i'm just going to turn off snapping we don't need that on now now with both of these loops selected we can press ctrl e to bring up the edge menu and choose bridge edge loops to fill in the gap we can tab to object mode and press ctrl 3 to add a subdivision surface modifier we can already see this really good flow of polygons around the mesh and if we change it to smooth shading we can see our shape in all of its subdivision surface glory tab to edit mode and maybe turn on the on cage button we can see that the whole thing is only 142 vertices now you might think the connection could be sharper and that's easily done by adding a control loop in between the edge border just press ctrl r to add one and there's a dialog box down here for loop cuts and what we need to do is change the interpolation to linear and set the smoothing value the slider goes up to four which gives a good sharp connection but you can actually enter any value in here i don't generally like to go above eight it's not creasing or doing anything unusual it's just altering the actual position of the vertices in a way which naturally sharpens this connection i would normally mark this in red as a control loop so i can change it later if i decide to maybe it's part of a spaceship or a gun or a flower or an engineering part who knows what you can make with it and we'll find that because it's a proper subdivision surface model it'll react really well to all of blender's other modeling modifiers uv unwrapping and texturing it will be simple transparency and sub-surface scattering will all work correctly now i'm just going to apply all the transformations let's add an array modifier make a 10. add another one uh and increase it in z this time maybe it's a a ladder or a roller coaster track increase the array count here to 10 and it's a grill or a fence it probably needs to be shaped so i could easily add a simple deform modifier gently to bend and start creating shapes add another simple deform modifier or bend and twist it on another axis we can safely create all sorts of shapes using deformers lattices waves cloths soft bodies armatures anything it'll be easy to manipulate because the geometry is light and sensibly arranged and at any time the subdivision surface modifier will be able to make it so that we can view it from any distance and the curvature will be perfect i can add and remove modifiers at will and change the initial shape again i can just select groups of faces and still have the ability to move them around to create more interesting shapes and i can always add more loops which will follow the topology because the topology is good it was much quicker to make than any boolean cleanup effort would have been and the result is immeasurably better there are similar subdivision surface solutions to every modeling test and i'll try to teach them all or all the ones i know anyway animators rigorous textures renderers even other modelers will all be very keen to work with the models that you create because they'll have this level of flexibility well that about wraps it up for joining uh cylinders or curved surfaces hopefully you'll see it's uh simpler than you might have realized and we can move on to talk about something else in subdivision surface modelling or maybe do the queen

Channel: Ian McGlasham

Views: 29,774

Keywords: Hard Surface, Hard Surface Modelling, Blender, Blender 3D, Blender 3.0, blender 3, cylinder, cylinders, connecting cylinders, joining cylinders, topology, good topology, topology in 3d, subd, sub-d, shrinkwrap, shrinkwrap modifier, blender topology, quad topology, quads vs ngons, subd vs boolean

Id: IS2LPVNp6SE

Length: 13min 8sec (788 seconds)

Published: Fri Mar 04 2022