topic Re: Extend surface issue ( question ) in Alias Forum

Extend surface issue ( question )

Anonymous — Wed, 20 May 2015 15:48:47 GMT

Hi, im new to Alias and i have a question if someone doesnt mind answering.

Im trying to extend a surface but at a certain point it stops extending.

Im sure there is a good explanation for it.

Have a look at attached, in one example it works flawlessly in the other one it doesnt.

Re: Extend surface issue ( question )

San_Escobar — Wed, 20 May 2015 16:12:46 GMT

Hi Yasick1

Briefly looking at your Patches, my guess is that for a simple form you have a non-uniform CV hull there. Sample 23, which may be leading to extension of the surface to be limited.

Where on sample 52 it’s a bit more uniform so, allowing to have certain length of extension.

Could you share your data? those patches so that I can take a look at it.

HTH, Have nice weekend.

if this solved your issue please mark this posting "Accept as Solution".

Or if you like something that was said and it was helpful, Kudos are appreciated.
Thanks!!!!

Re: Extend surface issue ( question )

duaxiong — Thu, 21 May 2015 00:50:49 GMT

Put a Curvature plot on the upper edge of your surface; if you see a spike in it, then that is probably what is causing it.

It would also help if you got rid of that diagonal section that cuts through your wheel arch.

Re: Extend surface issue ( question )

Anonymous — Thu, 21 May 2015 05:22:27 GMT

file attached,

thanks for your help. Hope someone can explain for certain why its happening.

Re: Extend surface issue ( question )

duaxiong — Thu, 21 May 2015 06:14:40 GMT

I put Curvature plots on both your surface and the curve that it was built from.

Notice how the plot accelerates sharply at the end. If you were to continue with this rate of curvature, you can imagine how it can continue curving so much that it will loop back upon itself. How quickly this happens will depend on the rate of acceleration. If you Extend it far enough, any curve that is not a straight line or an arc will eventually loop back upon itself.

In this case, you can Extend the surface up to the end of the Curve and maybe a little bit further (not that you should). Use Birail or Square to finish off the rest of the fender.

Re: Extend surface issue ( question )

Anonymous — Thu, 21 May 2015 06:53:30 GMT

thanks alot for your help.