how to add a half cone please?

#3
Or, even more easy, create a cone, select the top point and bevel it down.


Wrote earlier:
(This way, like in Frank's second example, you avoid ngons).

This is not true in Cheetah, sorry, may fault.
 
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#5
  • Create a cone
  • Set the radius to required value
  • Set the height to twice the required value
  • Set the sections height to 2
  • Make the cone editable
  • Go into Point mode
  • select the point of the cone and delete it
  • Select Tools->Polygon->Fill Hole
  • Click one point on the open end of cone to fill that space
 

Helmut

Active member
#7
* Frustum (truncated cone or pyramid)
* To maintain full control (nothing made editable, parametric objects remain for flexible customising):
* Use a standard 0° - 360° cylinder and add a taper modifier.
* Curvature = 0 and strength = whatever you need to achieve the geometry of the conical knob.
* For bulbous / hyperboloid knobs use the curvature´s ±parameter.

* Not to be confused with frustrum, but I leave that topic to the verbose and prolix poets of the C3D community :tongue:
 
#10
  • Create a cone
  • Set the radius to required value
  • Set the height to twice the required value
  • Set the sections height to 2
  • Make the cone editable
  • Go into Point mode
  • select the point of the cone and delete it
  • Select Tools->Polygon->Fill Hole
  • Click one point on the open end of cone to fill that space
If you mean the one that ZooHead show, yes, I understand, and this way is quite similar with the one that Helmut show, right?

Alex
 
#11
Here´s a file.
Look at the position values of the box, the "Boolean" operation is set to "Subtract" and get used to the hierarchy:
PS: Boolean operations will cut, add or show the overlapping (intersection) of different objects like in 2d vector editor software.

Cheers
Frank
 

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#12
Here´s a file.
Look at the position values of the box, the "Boolean" operation is set to "Subtract" and get used to the hierarchy:
PS: Boolean operations will cut, add or show the overlapping (intersection) of different objects like in 2d vector editor software.

Cheers
Frank
Oh, My God, it is really amazing... quitely beyond my imagination, thanks a lot, I think can do more creative by this way.:icon_thumbup:
 
#13
I think can do more creative by this way.
I remember, when I started modeling, I discovered them and used it extensivly. But as soon as I had a modeler on my hands which was capable of real subdivision, I saw that I just had lost time creating things this way. Should have learned to create clean geometry from the beginning.

Don't get me wrong. They are important to have and are often a good fast way out. But you usually don't create clean geometry with booleans.

Don't forget, in reality there is (almost) never a clean sharp edge. You need to bevel the edges; and with the resulting mesh of some boolean operations, this is sometimes hard to achieve.

If you use subdivision, then the boolean meshes are mostly, if not always, unusable.

So use them with care and try to avoid them. They are a dead end if you really want to learn modeling.
 

ZooHead

Active member
#14
I remember, when I started modeling, I discovered them and used it extensivly. But as soon as I had a modeler on my hands which was capable of real subdivision, I saw that I just had lost time creating things this way. Should have learned to create clean geometry from the beginning.

Don't get me wrong. They are important to have and are often a good fast way out. But you usually don't create clean geometry with booleans.

Don't forget, in reality there is (almost) never a clean sharp edge. You need to bevel the edges; and with the resulting mesh of some boolean operations, this is sometimes hard to achieve.

If you use subdivision, then the boolean meshes are mostly, if not always, unusable.

So use them with care and try to avoid them. They are a dead end if you really want to learn modeling.

Good advice. Boolean operations seem so tantalizing for beginners,
but can lead to problems as you try to increase realism with subdivision.

If you use the Subdivision Modifier before the Booleans they work well.

Cheetah puts a Crease in to keep a sharp edge
This is a good way to simulate freshly machined
metal which has edges sharp enough to cut skin.

 

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#16
Zoo, of course you're right. In your example it would even be easy to bevel the crease a little bit. Such sharp edges still stay the exception.

But I tried to nudge the guy in the right direction, i. e. not using booleans excessively in this step of his 3d learning process.

The problem with box modeling is (well, one of the problems) that it's not how we're used to build things in reality. It's quiet another thing with sculpting or carving. The last is in many aspects quiet similar to use booleans (even with the possibility of adding things).

It's even more so with patch modeling or lathe (which would be a way, too, to create cones of any sort).

And most of us are lazy. We almost always try to get the results with the least effort possible, often cheating and hacking our way through a task instead of proper learning it. It's the high art of laziness to work a lot in the beginning (i. e. learning) to have less problems later on (I'm sure you function in that way but most people don't). In this case, where somebody asks quiet a lot of questions (nothing wrong with that in my opinion), something seemingly easy is the thing to jump on.

And while you and me can use booleans as much as we like because we know how and where, and especially how to clean up resulting geometry if necessary, a beginner can't know that. He has to learn first the other methods which is quiet a lot of work and by no means an easy task. And this process never stops (which is something I love about this kind of work. It never gets stale). It doesn't matter how much you know (or think you know), there's always something new to learn or a situation where you still struggle with getting the desired result.

So, to reinforce my point, we should try to nudge beginners in the right directions. It's already hard enough for them :smile:
 
#17
Hasdrubal:And this process never stops (which is something I love about this kind of work. It never gets stale). It doesn't matter how much you know (or think you know), there's always something new to learn or a situation where you still struggle with getting the desired result.

Yep.:icon_thumbup:
 
#18
If you mean the one that ZooHead show, yes, I understand, and this way is quite similar with the one that Helmut show, right
Very similar. I try to set numeric values early and often, rather than relying on manually scaling shapes. This method gets rid of the inner extrude. If you need a cylindrical base on the bottom, you can Loop select the bottom edge of the cone and Extrude (where you can use the quantize value to set the exact height).
 
#19
I remember, when I started modeling, I discovered them and used it extensivly. But as soon as I had a modeler on my hands which was capable of real subdivision, I saw that I just had lost time creating things this way. Should have learned to create clean geometry from the beginning.
Many, many years ago, I helped beta test Bryce2, which had just added booleans. As everyone was learning how to use them, we wound up competing to see who could use booleans with the Bryce objects (Sphere, cone, cube, ring. Just the very simplest of primitives) to model a toilet. The beta-sharks came up with some amazing solutions.

Even though the software has been extinct for half a decade, Bryce still has the strongest boolean engine I know of. While most software I've used starts to choke when you put a boolean inside another boolean, in Bryce, I've regularly gone a dozen live layers deep (Bryce has no polygon modeling tools).
 

Helmut

Active member
#20
Booleans:

* Using Boolean operators for simple additive / subtractive tooling generally is a questionable method. You may as well spend the time and devise a clean and tidy mesh. However, once you get to more complex geometries, there is no way past it.
* Constructing the attached gadget (used in a specific type of scaffolding) without Booleans would be matter of numerous & laborious calculations and point shifting, taking a few days. Using a Boolean you get there in 3 minutes plus a bit of fiddling.
* Our Good Doctor has achieved an extremely clean topology with C3D´s Booleans. Yep, you need to fiddle and fine-tune parameters of the components to synchronise meshes for optimising the Boolean calculated by his algorithms. Once you know where to tweak the mesh there will be excellent results.

* Animating Booleans can produce complex and weird effects. The major problem is that you (well, I) mostly can not visualise these effects. These are shape-shifting phantasmagorias which do not exist in the real observable 3D environment.
* Conceiving a Boolean hierarchy with 7 layers (as MonkeyT mentions about Bryce™) seems to be beyond my intelligence. But then, again, I am not a student of Benoit Mandelbrot and fractal geometry :frown: :confused:

* Also, there are no hard and fast rules for 3D modelling. Arch Viz, stage design, engineering, human modelling, scientific concepts, 3D printing (and a few more) are far too different to be comparable.
 

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