"Welding" Two Objects Together

"Welding" Two Objects Together

I want to create a smooth transition between two objects joined with a boolean creator - something like a weld joint - where the transition between the objects is smooth and not abrupt. Any insight would be appreciated.

-Steve
 
Hi Steve.
Maybe a screenshot of the border, where the transition take place could help here. Guessing without specific information wouldn´t be a help; maybe cut of the opponent polygons and try building a bridge, with a ringcut afterwards and a "move normal" of the ring. Just guessing.....

With kindest regards
Frank
 
What you're really looking for is ... tada ... a bevel / chamfer tool:

http://www.cheetah3d.de/forum/showthread.php?t=1514

If you check this thread you'll see how I can approximate the effect by extruding the edge, but this is annoyingly manual.

Note that since I'm a subdiv modeler by inclination, a simple bevel tool (one interpolation) is all I'm asking for. A chamfer tool (which, ideally, would let you pick a profile) would be spectacular. I'm not asking for that, but you might ;-)
 
Maybe a screenshot of the border, where the transition take place could help here.
Thanks for the help, Frank. All I'm trying to do is make the joint between the sphere and cone a smooth and gradual curved transition so it appears to be a single entity.

-Steve
 

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Hi.
That is really easy to achieve without boolean&bevel tool.

1. Pick a sphere and a cone. Bring the two in position in Front view.
2. Make sure both objects have the same amount of longitudinal sections, this will speed up the progress.
2. The cone needs 2 sections at it´s height, because a ringcut won´t work here.
3. Now make both objects editable.
4. Make the sphere invisible and delete the top point of the Cone.
5. Make sphere visible again. Make an area select starting at the bottom of the sphere, till you reach an diameter alike the cone at the transition point. Hit "backspace" for deleting these points&polygons.
6. Drag the Cone onto the Ball in the Object browser. Go >Tools > Import Children. Select Cone again and hit Backspace for deleting. You will now get one object.
7. Use "Bridge tool" to connect the 2 parts.
8. In Edge mode select the edge loop between, say the border and make a Normal move. If you want it more smooth, additional ring cuts&normal move of the loops will do the job. Done.


With kindest regards
Frank
 

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Part 2

Hi.
Another very comfortable way to build such a thing is to use a spline and the Lathe creator. This will give you the advantage of controlling the whole transition while it stays editable unless you collapse the creator.
(There are of course more ways, but I think the spine way will give you the most support on this.)

With kindest regards
Frank
 

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Bevel tool within booleans?
No, a (perfectly ordinary) bevel tool to use on the output of booleans. Indeed, (it would achieve) exactly what you did manually.
 
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This is REALLY easy to achieve with an ordinary bevel tool.
 

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And with a bevel tool you can just as easily work on seams between arbitrary objects ... not just radially symmetric objects that can always be lathed.
 

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As an aside: Frank's lathe approach for building your (specific) object is definitely better than using booleans. Booleans should be a tool of last resort since they tend to leave you with fairly badly mangled meshes. (This is not a flaw of C3D*, which does booleans perfectly well, but a problem with booleans.)

Booleans do work very well as a ray-tracing (versus modeling) trick, but that's another story.

Here's a simple before and after shot (the before image was faked because C3D won't display the edges of more than one object at a time).

* Well... actually... it kind of is a problem with C3D. C3D triangulates (or "tesselates") the faces cut by the boolean operation, whereas Silo 3D simply converts them to n-gons. This means that the Silo 3D modeler has more control over how mangled those faces end up (because he/she can manually triangulate them) whereas with C3D you're likely to have to delete and recreate faces to fix your topology. Also, C3D's approach seems to lead to more mangling than is strictly necessary (the left-of-center face in the "after" shot is way more mangled than it needs to be). I suspect this is because C3D splits a face for one edge, then splits the (now split) face for the next edge, and so on. Silo's approach -- which is happy to live with arbitrary n-gons -- doesn't run into this problem.
 

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Wow, thanks for the info about the different approaches! It's good to know the advantages and drawbacks of each approach. It helps me determine which is best for a given task. Very helpful for a newbie like me!

-Steve
 
Is that feature in C3D? I sure can't find it. Upon closer inspection of your screen shots, they don't appear to be from C3D. I have C3D 4.3, which I think is the latest.

-Steve

Hi.
No, not yet, but everyone (OK, nearly everyone) is waiting for it. Martin has good plans on this. Just a matter of time.
Wit kindest regards
Frank
 
Sorry Shotster -- I should have said the screen shots were from Silo 3D. (A really good companion tool to C3D, or any 3D program really.)

I believe that Blender's bevel/chamfer tool is pretty good. So you could export to some file format Blender reads (e.g. OBJ) and then make the change (after struggling with Blender's various UI quirks ... just how do you select something? Oh right, you need to be in edit mode...) and then bring it back. Blender is free, small (<20MB), and runs well on almost any hardware. It's a pain in the ass to use most of the time, but its amazing functionality (and free-ness) makes it one of the first programs I install on any computer I use.

Wings3D has the feature and is also free. It's a similar tool to Silo 3D (i.e. a dedicated modeler). Its UI is quirky, probably a bit harder to figure out than Silo 3D (which is about as approachable as Cheetah 3D) but not as nuts as Blender. Warning: I've had trouble getting it to work on Intel Macs (and have stopped using it :-( ).

Final Note

Almost any 3D modeler is going to have to get used to using multiple programs to achieve a specific desired result. If you wait for your favorite program to get some specific feature you need, you'll discover that some other new feature will have been added to a rival program. Even the big boys (like 3DS Max) don't do everything, or do some things poorly (Silo 3D -- a $159 program -- is widely used by folks who have licenses for Max, XSI, and/or Maya).

One of the first 3d models I built (back in 1990 :) ) was a chess set. I wanted it perfect. I was using Strata 3D 1.4.2, which didn't have booleans ... so I couldn't cut a slot in the bishops' heads. I ended up using Minicad just to model the heads of the bishops. The rooks ("castles") were also impossible to do without booleans, so they got done in Minicad as well.

Finally, I couldn't figure out how to put a seven pointed crown on the queen's head (Strata did actually add mesh editing tools shortly after I finished the model). In the end I wrote a program (using hypercard) that exported a Swivel 3D script that when opened in swivel 3D assembled, polygon by polygon, a perfect seven pointed crown).

So, to build a simple chess set it took three 3d programs and HyperCard.

Edit: hey I found a copy of the rendered chess set :)
 

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