problem with creating a smooth form

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 From:  ello
3631.1 
Hi there,

i am struggling now for quite some hours creating a smooth form. attached is a moi file which shows my current form. it has three outlines and my approach to create a solid form according to them. but i am simply not able to create smooth transitions so the form looks better. fillets dont work...

any help is really appreciated,
kind regards,
ello
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 From:  Michael T. (MICTU_UTCIM)
3631.2 In reply to 3631.1 
Hi ello,

Take a look at this file. I trimmed your original curves and then used the sweep command with maintain tangency. I then joined the four surfaces into a solid. Is this closer to what you want to achive?

Michael T.
Michael Tuttle a.k.a. mictu http://www.coroflot.com/fish317537

EDITED: 4 Nov 2010 by MICTU_UTCIM

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 From:  ello
3631.3 In reply to 3631.2 
thank you very much, michael,

that seems to come much nearer to what i want. and it opended my eyes to look for other ways to reach my goal. it still has some strange curve at the top front.
how exactly did you use sweep here? i tried out network within three splines and i guess i have to check those alternatives a bit more...

cheers,
ello
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 From:  Michael T. (MICTU_UTCIM)
3631.4 In reply to 3631.3 
Hi ello,

The attached JPEG should help explain the order of how I selected the curves for the sweep.

Let me know if you come up with any other cool ways to put this together.

Michael T.


Michael Tuttle a.k.a. mictu http://www.coroflot.com/fish317537

EDITED: 4 Nov 2010 by MICTU_UTCIM

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 From:  Michael Gibson
3631.5 In reply to 3631.1 
Hi ello, so that method of making a solid uses all extrusions from those profile curves. An extrusion is a surface that is completely straight in one direction, and when 2 straight things are intersected it makes for sharp corners.

If the final shape is intended to be very rounded and kind of melty looking all over, it is not very well defined only by extrusions from 2D profile curves. You will generally need to create some surfaces for such things with other methods that generate some curved surfaces to start with (like Sweep for example) rather than only straight surfaces.


Please check out these previous posts for some ideas on strategies for modeling this kind of shape:

http://moi3d.com/forum/index.php?webtag=MOI&msg=1002.1
http://moi3d.com/forum/index.php?webtag=MOI&msg=3137.1

- Michael
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 From:  ello
3631.6 
thank you both! i guess i have got the idea now.. i'll show the results than..

cheers,
ello
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 From:  ello
3631.7 
once again i have a problem here.. i now created the base form, but cannot create fillets on them. for obvious reasons as the surface hase those lines meetingat a single point...

any ideas??

cheers,
ello

edit: added file
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 From:  Michael Gibson
3631.8 In reply to 3631.7 
Hi ello - yeah it's not going to be good for filleting to have areas like this where your side surfaces get all narrow and collapse down to a point:



Fillet doesn't know how to cross over edges from other surfaces than the ones that are directly joined to the edges being filleted, so basically it is limited to have to be smaller than this edge here:




It would help a lot to make a more simple and regular topology to your surfaces rather than having them come to that "pole" collapsing point at the tips.


Did you see some of the other strategies that I mentioned previously:

http://moi3d.com/forum/index.php?webtag=MOI&msg=1002.1
http://moi3d.com/forum/index.php?webtag=MOI&msg=3137.1

Those would probably give you a topology with a better shot at filleting.


What radius of fillet are you trying to create? It might be possible to get some fillets on your existing shape here using the lower level surface/surface fillet. That can be applied if you break your model into individual surfaces using Edit > Separate and select 2 surfaces at a time and run fillet. That creates the fillet using a different technique than the edge-based filleter, and it can can build some kinds of fillet pieces that the edge-based one has difficulty with.

For example here I broke your model into individual surfaces with Edit > Separate, and then selected these 2 surfaces:



Then running Fillet will build this fillet surface:




That surface/surface fillet is kind of a more low level tool than the edge-based one, it will give you some various surfaces and you will need to do some trimming and joining of those surfaces to get back to a solid.

If you know you want to fillet something, it does help a lot if you create a more regular sort of topology for it though, you kind of want to plan in advance that your shape is not going to be poorly configured for filleting.

- Michael

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 From:  ello
3631.9 In reply to 3631.8 
thank you for the hint! i didnt know that i could use fillet between surfaces.. i guess i am on the way now :)
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 From:  Michael Gibson
3631.10 In reply to 3631.9 
Hi ello, it can be a bit tricky though since you end up with a lot of small pieces that need to be managed and trimmed.

If you can let me know what radius value you wanted the fillet to be, I could give it a try to see if it is going to be feasible or not.

- Michael
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 From:  ello
3631.11 In reply to 3631.10 
Hi Michael,

i managed to create it by using a mix of sweep, network (for the rounded edges) and loft. i created curves for all the tricky places. finally i joined all the surfaces and now i have a quite nice surface i can work on with...


cheers,
Ello
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