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I had needed help with a similar situation involving this object in another page here, which was incredibly helpful as I learned a bit more on how blender works and such. But after many failed attempts and practically starting the object over about 15 times and up, I feel I've reached "that point" where I really could use some help as I learn more and get better at using Blender.

I'm trying to create the center body of a grinder. I always start of with a cylinder and tried variations of high-low vertices/different fill types in different attempts at the beginning to star off right. Above the body, Ive already created the hole (2 sets/rows) and spike arrangement using array and curve modifiers. But it seems that no matter how many edge loops or subdivisions and variations of such I try on the actual body of the grinder, every time I intersect everything using Boolean, 1 at a time, the center always distorts making a subdivision modifier act crazy and not creating the holes properly with or without the submod. Since this is gonna be printed out, I need to make sure that based off what all tutorials have told me and info I've read here, that the topology is precise for best printing results. I don't know what else to try. I really wanted to get this "on my own" and so I couldn't find any more helpful youtube videos so here I am.

I should mention that at this point, Ive erased the body and am ready to start from zero creating it if someone can guide me and explain why it has to be created such way. I really want to get good at this. I'm super impressed with some of the things people have been able to create with Blender. The type of images that you know are real until they show you the wireframe version. :0..but yeah Your help would be greatly appreciated.

enter image description here enter image description here enter image description here

Out of all the times I made and remade the body, I managed to get one variation that I used in a video to be able to show my idea. This model didn't have the holes in the middle, because as soon as I added them, the submod went crazy. https://www.youtube.com/watch?v=_6CewS_i8Yo While those black shadow areas do look interesting, they're not a result of my modeling but of the submodifiers effect. Not sure if actual size of the objects to be printed out matters in the specs but heres the idea. So it is the topology? Whats the best strategy to begin building it correctly? Empty cylinder and extremely extrude from there?

enter image description here enter image description here

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  • $\begingroup$ can you add some reference pictures and concise specifications? It is a good idea to make use of symmetry when possible. $\endgroup$ – Firewill Jul 20 '17 at 3:40
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    $\begingroup$ Your fundamental problem is relying on Booleans for modeling. Booleans are a lazy way of achiving a final result, use proper modelling techniques and good topology instead $\endgroup$ – Duarte Farrajota Ramos Jul 20 '17 at 3:47
  • $\begingroup$ @Firewill There we go $\endgroup$ – Nebula 480 Jul 20 '17 at 4:26
  • $\begingroup$ I showed you detailed instructions for achieving a proper render with this model: blender.stackexchange.com/questions/84455/… If you would take another look, I'm sure you would find the solution to the sub-surf problem. $\endgroup$ – bertmoog Jul 20 '17 at 4:50
  • $\begingroup$ booleans often give results that are difficult to fix, also see blender.stackexchange.com/questions/74922/… $\endgroup$ – m.ardito Jul 20 '17 at 8:46
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As was already recommended in the comments, don't use booleans, they are a beginners trap. They can be extremely useful but they are also dangerous. Until you understand how edge flow, tensions and general topology work I'd advise to stay completely clear of them.

The "perfect topology" doesn't exist, what you can make is clean topology, clean topology is made of mostly quads (four sided polygons) of very similar edge length, there are other rules and guidelines, but as long as you adhere to those two points you will be in the clear for the most part.

Have a look at the site Duarte linked: Topology it has a lot of very good examples.

This object as far as I understand has 16 holes and 8 spikes, so you can make just an 8th of the full spin and then instance it around a circle using the array modifier and an empty.

Like this:

Create a piece matching the "period" of your full model, in this case this is dictated by the spikes, there are 8 spikes, so you need to pick a 45° section and model it:

base topology

I'm using looptools to make sure my square holes are perfectly square, you can do something similar without enabling looptools by using spherify, ALT+SHIFT+S.

This is how it looks with Subsurf:

SubD topology

Finally you use an empty and an array modifier to copy the piece and rotate it around its origin:

enter image description here

Hope this helps, I'd advise starting over and keeping the un subdivided mesh fairly simple.

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    $\begingroup$ While this is an ok solution for this particular model, what if the shapes were a series of tetrahedrons, squares, and cylinders, or even complex shapes? What if the shapes were not perpendicular to the surface? Booleans would allow for precise placement that would normally require a lot tweaking of the mesh if going the route that you propose. $\endgroup$ – bertmoog Jul 20 '17 at 13:41
  • $\begingroup$ @bertmoog I followed your steps and understood better what was going on but I would always get stuck at the 3rd when using boolean. It wouldn't make the holes properly. Simple things like making a piece set 45 triangle with that simple looking subdivisions are....well I don't know where to start. I'm so new at this $\endgroup$ – Nebula 480 Jul 20 '17 at 16:10
  • $\begingroup$ @bertmoog Booleans can be a time saver, for sure, but since this question mentions topology I feel it is important for people to understand how topology works, once you grasp the rules the reasons why certain operations fail or the shading gets messy become apparent. We are working with polygons first and foremost, even when using booleans we still use polygons. I also have a bias towards proper topology since I dabble into gamedev and animation, to me, a properly modelled object is admirable and holds value on its own. $\endgroup$ – Firewill Jul 20 '17 at 16:18
  • $\begingroup$ @Firewill - no, I totally agree... dressed is best. All I meant was the Subdivision mod is a double-edged sword. In your example, you're relying on it to shape the cylinders and cone, but if he were to need a cube too, something's gonna fail. $\endgroup$ – bertmoog Jul 20 '17 at 16:27

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