Hi Steve,

The error you talk about is more to do with continuity right ??, I did actually match & improve on G0 in Rhino but I wasn't
happy with the result due to the surface isocurves going to a single point, thats where I lost the control.

Building the surface as one is usually the best option in terms of overall smoothness and your first comment the other day
was 'spot on' as splitting the profile helped make a good surface as shown in your analysis. I say good because if you turn
the surface and look end on there is a crease when the surface again meets at a point.

Are there any other ways to build such a shape or how might it be possible to further smooth your example ?

Many thanks in advance,

Hi Paul,

>>but I wasn't happy with the result due to the surface isocurves going to a single point

Split the base control curve into 4(curve split at tangent/intersection) then network in MoI:-



This is the surface produced in MoI but viewed in Rhino:-




- manz

Hi Paul,

>>I say good because if you turn the surface and look end on there is a crease when the surface again meets at a point.

What did you use to check the surface? If you are just looking at the model in MoI then you may just be seeing an error in the created mesh not the actual surface.

- manz

This is my little example.
I took the MoI file as an .obj file directly into Carrara.
Most surprised how many of the various choices for networking would not or were not good!

Hi Steve,

Before I did as you suggested in your previous post I took the model into Rhino and shaded it, if you look you
can see a bad crease on the end.

This method of further splitting the curves is an excellent idea !! Thanks

There is one small area which still doesn't look quite right and im not sure how that could be resolved. Looking
at the profile of the surface you can see that the iso curves don't quite make it to the end of line and it is this gap
to the arc where the deviation is taking place.....this would also be a pain to machine in the area.

If you have any further ideas I would like to hear them. :-)

TIA

Hello Brian,

It's hard to say but I don't think your surface follows the curves both directions ?

Hi Paul,

Move the splitting of the base control line to the ends,.. it does less pulling on the end areas.:-




If there is still a problem, then I would suggest a surface "rebuild" in Rhino.

Hi Steve,

Perfect! - I have learned a lot using the network command in MoI and the various splitting of curves to make major
& subtle differences - Thanks for your time on this one.

I will be cutting this model in the morning :-)

karter
Is this ok?
(It's the same file with a different render setting._
Brian

ps. The MoI screen shot shows the only way I could get a nice smooth network result. Doing a left and right version and joining them.
(Sorry if I am missing the point somewhere but could not my end result be as clean/smooth as is required.?)

Hi Brian,

Thanks for the reply. If you look at the previous posts and Manz method of splitting the curves in a particular manner to create a network surface that works the best...try it and see ?

Building half or even quarter surfaces with limited geometry like I have requested will definitely cause problems with continuity after being mirrored into a full shape...maybe V2/V3 will have some matching capabilities that would help this cause.....

Thx again.

You must be cautious to use Network for this type of surface. When input curves are G1, the resulting surface might seem OK and will be valid. BUT there is usually a problem with the surface normal at the corners. Try to Offset the surface and see what happens... If you're not planning any downstream operations that will confilct with this (shelling, fillets, etc) then it probably won't be a big deal...

jonah

jonah
I can't get over how difficult this particular shape is.
I tried making it in several of my other subD and Nurbs apps also and MoI is WAY ahead!(Well I could not do it in any of them!)

What is it in this shape especially that creates problems I wonder?

Anyway, for use in my normal 3D rendering apps I at least got a fine result eventually---with thickness!
(What a time waster!)
Brian

Hi Brian,

You should be able to create the surface in other applications even poly apps, for example, I created the surface in Hexagon from the line data (the other poly programs would not import the line data, so did not attempt).

In MoI/Rhino you would build using "network", in poly programs you would use (as in Hexagon) "Gordon surface". I am not saying the resulting surface would be accurate enough for machining, but it can be easily modeled from the curves given.


- manz

Manz
1.Are you saying you created the same lines in Hexagon and enabled Gordon surface to them.
2.and/or you imported the line data to Hexagon in "?format" (from?)and enabled Gordon surface to the lines

Is it a Brian day? I can not do either!
Brian

Hi Brian,

>>or you imported the line data to Hexagon in "?format" (from?)and enabled Gordon surface to the lines

I converted the line data into DXF then imported into hexagon, I did have to weld some lines/curves to create the correct lat/long sections needed.


- manz

Thanks.
What a complex world!
Brian

>> What a complex world!

Unless you purchase MoI of course :-))