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Modelling advice

G

gking

New member
Hi all,

I am trying to remodel a brush handle that my company
currently injection moulds. The current CAD data has
been reconstructed from surface scans of the tool and
therefore have no history.

View attachment 5738

I want to remodel the part with a view to making some
subtle modifications to the shape. I am interested to
know how others would approach this.

I am running Creo 2.0 with ISDX.

Thanks
G
 
Whta do you mean by remodel? Do you what to recreate it from scratch to have full control over model?

If
so, I see here two basic issues if you are less involved in surface
modeling. Both are related to 3 sided surfaces - back and nose
area[search this forum through for approriate tricks, i.e design engine
toupee method).

Top and bottom surface can be made by VSS tool.

cheers

Jacek
 
another way to start is by doing the "top surf" with BB (Boundary blend) and then trim it . Create the surf using the green curves for 1 dir, and some curves (red) in dir2. Then trim using a projected curve (light blue in my pic) . Handle the sidesurf using VSS or BB, and do as Jacek says regarding the nose and back area. (and yes the image is done in paint....
smiley2.gif
)


//TobiasView attachment 5741
 
You have ISDX, it Does a good job of handling 3-sided surfaces, so no worries for that part!
you can also model it using Freestyle feature which is a lot faster than conventional surfacing and gives you a great deal of control as well:
Freestyle.PNG
 
great result Solidworm.

I catched myself I rarely ever use this tool, altought it seems to have great potential.

I noticed ISDX solves 3 sided surf condition in same way Boundary Blend does.
 
Thanks for all the feedback guys. Here a few things,

@solidworm - i've played about with the freestyle feature
and it certainly is very powerful, however you cannot
define any tangent or draft controls to the surfaces.

@muadib3d & tobbo - until now i havent had the need to do
any of these 3 sided surfaces. i have done some
experimenting (see attached)

1. this is created using the style feature with 3 curves
2. uses the same 3 curves and a BB
3. uses the same 3 curves and the method of trimming to
create a 4 sided boundary above.

Is ISDX & style the best way to handle these features?
It certainly is the quickest.

View attachment 5750
 
Things are hectic, busier than ever before. Into production this week with the new line of heaters, tempers are fraying and everyones on edge but if it all went smoothly it would be no fun.


Hope you're keeping Mr McCay on his toes!!??
 
I do not see any differences between 3 sided surface created in ISDX or Boundary Blend.

Maybe ISDX is less complex to use, maybe...

The fact is - there is a difference between 3 sided and four sided surface. If you encounter more complex issues, you will see(however it is clear other software aka SW, solves this problem much better from what I`ve seen)

so, core difference is hidden from you. To see it you should run Mesh analisys to see real nature of surface.

View attachment 5751
 
@Michael - good to hear they are keeping youse all busy:)
Yeah keeping Marcus on his toes. Have you upgraded to Creo
yet?

@muadib3d - thanks. the mesh does show the differences.
 
you can add a good enough draft on freestyle models if you want, try your luck with "blend tangent to surfaces" feature. here's an exaggerated draft angle added to my freestyle model:
draft_on_freestyle.png
 
I'll have a play with this feature and see how it works
(never used it before).

Another thing I need to consider is controlling the
thickness of the handle part. Need to maintain a constant
wall thickness of no more than 7 mm to match the current
part for injection moulding cycle time etc. If i'm using
style and ISDX any ideas?
 
@solidworm, "blend tangent to surfaces" is a good tip, and nice to see that its not only me who use the "advance features"


//Tobias
 
Guys, thanks for all the help and advice so far. I have
progressed this really well.

I have a general question regarding the use of the style
feature vs BB & VSS etc. What is the better method?

So far I have created all my control curves as splines in
sketches and have successfully formed good surfaces using
both techniques. I am curious to what you all prefer or
regard as the best technique for surfacing. and what if
any gives best results.
 
gking said:
I have a general question regarding the use of the style

feature vs BB & VSS etc. What is the better method?
Click to expand...

making curves in ISDX is faster, more stylish, intuitive. ISDX gives more control over curves in some areas(specialy curvature on both ends). I use this heavily for conceptual modeling, when the "form" is up to be found.

I rarely ever use ISDX to create surfaces or trim them. Same regarding Intersection or Projection of the curve.

VSS is separate topic to be discussed. Fankly speaking - you use BB when you have all your curves there. Instead I use VSS when I do not want to "gues" about curves network, I just wany surface to be mathematicaly controled.

At the end it all depend on habbits - I began to play with surfacing without ISDX, now when I`ve got all these "whistles", I catched myself on doing things in old ways.
 
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