volume's in GSD

[thixoguy]

Hi All,

In the GSD workbench when/why would you use volumes? Why not simply create a solid straight off in the part design workbench?

thanks, thixoguy

 

[5050t]

...because volumes are surfaces not solids. Usually used for analytical purposes.

 

[thixoguy]

5050t,

Thanks for quick response! Excuse my ignorance but could you not use a solid for analytical purposes? I am trying to understand if the use of volumes might provide some advantages in mould design(which is primarily what I do)
I come from a UG background and from what I remember any closed volume was essentially a solid(someone correct me if I am wrong).

thanks, thixoguy

 

[solid7]

"Usually" used for analytic purposes? How's that???

There are entire projects modelled with surfaces, rather than solids. There's no simple answer to "why use surfaces instead of solids". I suspect that I haven't got a clue why some people do it, or what processes they are trying to accommodate. But to keep this short and tidy, volumes are the GSD equivalent of solids. This allows you to perform boolean operations on surface entities.

Thixoguy - you don't have to use volumes strictly with other volumes. They can also come in handy if you need counterbores in surface data, for example. I've seen volumes used quite a bit in PowerCopy. And, of course, there are times when you are working with imported data, and maybe you can't make a solid. Using volumes may also help you to get a closed solid, by putting in operations BEFORE trying to close.

The possibilities for using volumes are pretty endless. They're a good thing.

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CAD design engineering services - Catia V4, Catia V5, and CAD Translation. Catia V5 resources - CATBlog.

 

[thixoguy]

solid7,

Thanks for the response.Prior to using UG I used a software called Cimatron IT(it had a solids package but it wasn't very robust and has since evolved into Cimatron E which from what I understand has much better solids capabilities). I used to model complete moulds in surfaces exclusively.
Your explanation for the uses of volumes provides some clarity on the issue. If I understand you correctly volumes are used for trimming or modifying existing or imported surface files. I assume if one is starting a part from scratch it would make more sense to work directly in solids, that is, extrude a solid body as opposed to a volume.

For those who do mould design(DBezaire are you there?) is there any advantage to incorporating volumes in mould design?

thixoguy

 

[solid7]

If I understand you correctly volumes are used for trimming or modifying existing or imported surface files.

Well, not necessarily. One COULD model in surfaces only - and indeed, some do. However, I'm just saying that most of the cases that I'VE personally seen, are "legacy" operations, as I described.

I think - based on my own usage - that volumes get used quite often in tool design, especially surface conforming tools. In my case, I find it easier to use the original surfaces, and create backside tool geometry, then add in tooling features, and close the volume last. Backside tooling features many times are not an "offset" from front, and sometimes, when they are, cannot be offset due to small radii on the tool side. Aside from that, solids let you get away with making sloppy mistakes, where surfacing is MUCH less forgiving. If that sounds like a bad thing, see what your reaction would be, if a shop halted fabrication on a $3/4 million tool, and was waiting your changes. I've seen those types of things happen alot, and I'm a big believer in surfacing for complex facesheets, layup mandrels, and certain types of dies.


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CAD design engineering services - Catia V4, Catia V5, and CAD Translation. Catia V5 resources - CATBlog.

 

[DBezaire]

thixoguy - all my systems are HD2 license scheme. With this I do not have surface volumes. As for the design aspect, all mold components are 3d solid based. The part and seal off are a surfaced item. I agree with Solid7. Once we have obtained a core/cavity part we join core and seal off, cavity and seal off. From here we split in Part Design, a solid block for each half of the tool. These blocks are setup as an assembly. The remaining items are added using solid based features. You could use just surfacing to accomplish the same result visually, but downstream knowledge is not there. We have a default tool assembly with common components in place (adjustable via parameters).
If you look at core surface development, I generally surface it with most attachment features add to the closed solid.

Regards,
Derek

 

[thixoguy]

DBezaire, solid7,

Thanks for the info!


thixoguy

 

[catiajim]

The Volumes in GSD appeared at the same time as Hybrid Bodies - I suspect for the same reason (very large pacific rim auto OEM requirement). I believe they require the GSO license to show up.

 

[itsmyjob]

yes they do... need GSO for Volumes. We use GSO for splitting solide and mesh them.

Eric N.
indocti discant et ament meminisse periti ​