Inventor surfacing better than Creo

[SW]

A problem I have been having with Pro/Engineer for years
involves offsetting or thickening surfaces. When the radius of the
surface drops below zero the offset fails. Why can

 

[design-engine]

Ill forward this thread to the proper persons.

 

[SW]

Bart,

Doubtless you have a similar requirement?

Sam

 

[solidworm]

Are you sure you want that? i think the whole purpose of the thickening tool is to have a solid with with constant thickness, that's what is important in plastic design. that's a wrong solution offered by inventor, it causes warpage and manufacturing defects in plastic design.

 

[dgs]

I think that newer versions handle this better, but
it's a good suggestion none the less. However, to may a
broad generalization that Inventor surfacing is better
based on this one issue is quite shortsighted. In fact,
surface offsets like this are a pretty basic feature (which
one could argue ought to be cake, I know), how about A
class surfacing like a faucet bottle? What about tangency,
curvature and the ability to control the surface contours
through design manipulations?

 

[SW]

I'm totally sure I want to do that. The images I posted are just
academic examples but there a lots of occasions when I just need the
model to work. I can sort manufacturing problems such as warp or sink by
adjusting the geometry later, adding a radius on the B-side or using my
engineering judgement to decide if its a problem depending on the
manufacturing method. I'm happy for Pro/E to warn me, but not just
"decide" it can't be done.



The approximate offset has been improved recently with the ability to
use normal or approximate offsets on individual surface patches but the
problematic patch is often a large proportion of the surface and the
Approximate Offset its just too approximate.



I was being a little facetious with my topic heading, I do think
Pro/Engineers surfacing capabilities are extremely good. There is a lot
more capability than Inventor. That said, the advanced surfacing module
is expensive and you get a lot more for your money with any of Inventor,
SaladWorks or SolidEdge. Back to the topic, I justify my continued use
of Pro/Whatever despite its continued inadequacies in usability through
its ability to model whatever I want to design. Not being able to offset
or thicken when the radius drops below zero is a huge problem with a
lot of the work I do and I just hope that Creo 2 has more to offer.



The ability to set surfaces or splines not to drop below a pre-set
radius as I manipulate them would be icing on the cake, but if Inventor
can manage it, surely the zero-radius offset is not too much to ask?



Cheers,



Sam

 

[dgs]

You won't get too much dissagreement from me on this,
there's certainly no reason Pro/E should be able to
continue to offset with a sharp corner once the radius
stops working. It's the logical solution, why not automate
it?

 

[SW]

I'm having the very problem right now. I have a skeleton part
controlling the surfaces on three parts. As I am trying to shape the
skeleton surface I regenerate the assembly between mods. Repeated
feature failure. I then have to trim the surface to get rid of a bit
that is causing the problem, only to find another part fails when I make
another change.



Yes, I could model the inside surface but the outside is the A-side, and
in this case I need to offset the same surface in both directions
anyway for different parts.



PTC, please...



Sam

 

[Bobson]

i would kill for this
as has been pointed out, its not always final data we are
working on, constant wall thickness is good practice but
in consumer/moulded parts its not always possible,
sometimes you want different offsets etc for mechanical
strength othr times just want a 'solid' model to help
with workflow later on.
If the external radii/form is offset to a point/edge it
would generally be quicker to fix/add to this geometry to
get the manufacturing solution rather than creating the
inner wall offset as another bunch of surfaces
surfaces?
The approximate offset isnt very approximate in my
working day!


Edited by: Bobson