Surfacing for everyday modeling

I'm doing some research for a user group presentation, and I'm just curious about how most folks use surfacing in everyday modeling. I know "everyday modeling" means different things to different people, but I'm aiming at the group of folks that doesn't necessarily do a ton of complex shapes.

Do you use things like:

- replace face

- move face

- fill surface

- extend / trim surface

- delete face

- untrim

- delete hole

- move body

- delete body

- cut with surface

- up to surface end condition

- up to body end condition

- loft surface

- loft a solid between surface bodies

- ruled surface

- radiate surface

- etc...

Basically anything vaguely interesting surrounding working with surfaces.



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However, a 1 doesn't mean I can do without it, it just means I don't use it alot, but when I need it I need it bad.

My present work is primarily machine parts which are by and large prismatic. Surfaces however make excellent sources of stable reference geometry that can be extracted and kept stable early in the feature tree as recommended by Ed Eaton.

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Hi, Matt,

1 on a scale of 1-10 Never had a need for it :-)
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That's interesting too. What type of design do you do?

Are you familiar with the commands and just don't see an application or do you not use them because you're not sure what they do?

Do you ever use solids to fill in little nicks in a part?

Do you ever find yourself closing a sketch with a bunch of lines that don't really matter just so you can extrude a solid or making a cut extrude to clean up a face?

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I've done more surfacing lately than ever before, so just because I'm not using something may not be because it's not just terribly useful . . . it may be because I don't understand how to use it (yet). Those are tagged with a Zero. SO, also on a scale of 1-10 where 10 is likeliest to be used on a part for which surfacing is necessary:

3 - replace face 0 - move face (don't know how to use it) 5 - fill surface 8 - extend / trim surface 7 - delete face 4 - untrim 0 - delete hole 0 - move body 1 - delete body 6 - cut with surface 9 - up to surface end condition 9 - up to body end condition 9 - loft surface 0 - loft a solid between surface bodies 4 - ruled surface 3 - radiate surface

One thing you didn't mention was Hide Body. I find that to be very useful to be able to see what I'm doing, and sometimes useful to show the end condition. Probability of usage (whether temporatily or permanently) approximately 8. Also the Combine (Bodies) function is quite useful when using a combination of solid modelling and surfacing techniques. I'd call that a 7.


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Thanks, Spork.

I'm trying to distinguish between body functions and surface functions, even though I know I listed a couple like up to, delete and move body

Show/Hide body is something I use on a per minute basis, can't imagine why I left it out. I try to avoid the need for a Combine, but still have to use it sometimes.

The discussion about how SW handles "bodies" is at least as interesting as the surfacing discussion. Someone else is actually presenting that discussion too. I hope to learn a bit about that so I don't have to keep learning the hard way!

7 - replace face (when it works, it simplifies things a lot) 1 - move face (best for imported solids) 9 - fill surface (this is like a magic wand, I love this one) 8 - extend / trim surface (extending is sometimes quirky) 7 - delete face (this is another underused gem) 6 - untrim (sometimes this will get you out of a bind easily) 4 - delete hole (really just untrim) 4 - move body (when cheating counts and offset doesn't work) 2 - delete body (not sure about why/when you should use this) 7 - cut with surface (a huge favorite rather than extrude up to) 9 - up to surface end condition (sometimes you gotta use it) 4 - up to body end condition (when up to next doesn't work) 9 - loft surface (use this frequently) 6 - loft a solid between surface bodies (usually as a workaround) 8 - ruled surface (quirky, but essential) 2 - radiate surface (when radiate won't work)
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That's a big one.

My design work tends to be plastic parts, and even if the part isn't a crazy shape overall, there's always some funky transition which can't be made with extrudes. I've found with plastics that the ruled surfaces are essential, even if they don't really work that well.

I should also add to the list things like Thicken, Knit and Hide Body as Spork pointed out.

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matt wrote (my comments interspersed):

replace face (when it works, it simplifies things a lot) When you can use it it's magical, wonderful, indespensible.

move face (best for imported solids) I'll have to look into this one. SolidWorks Help isn't very helpful.

fill surface (this is like a magic wand, I love this one) I like it too, when I can use it, which always seems to be not nearly as often as I'd like to use it.

extend / trim surface (extending is sometimes quirky) Quirky it is at times, but Trim less so than Extend. And Extend I use almost as much as Trim.

delete face (this is another underused gem) This is good, but Delete with Replace or Delete with Patch doesn't seem to work very often.

untrim (sometimes this will get you out of a bind easily) This one is Black Magic -- don't understand it at all, but it works wonders at times.

delete hole (really just untrim) Never even heard of it -- need to look into it.

move body (when cheating counts and offset doesn't work) Have seen many references to this lately, and I still don't have a clue.

delete body (not sure about why/when you should use this) Ditto, but I wonder if one can use it instead of Hide Body when you actually want to do it permanently.

cut with surface (a huge favorite rather than extrude up to) INSTEAD OF? How?

up to surface end condition (sometimes you gotta use it) Yeth, but am often frustrated by the inability to use if the surface doesn't extend beyond the sketch. I often have to use Extend surface or Ruled surface to make the boundary bigger.

up to body end condition (when up to next doesn't work) I never think of "up to next" as something preferable to "up to body"

-- can't figure how that works, but I'll try it. I do sometimes wish there was an "offset from body".

loft surface (use this frequently) Goes without saying, but so many options are confusing, and many of them very quirky (often much better than lofting a closed profile into a solid, however). I'm NOT complaining about too many options . . . just that there's too little explanation, as is true with almost ALL of the surfacing options.

loft a solid between surface bodies (usually as a workaround) Didn't know it was possible.

ruled surface (quirky, but essential) Extremely useful -- I find it strange that you can use a face of a solid with this option, but not with Extend (have to Offset with zero distance first to use Extend).

radiate surface (when radiate won't work) Huh? Nothing else does what this does . . . I don't know what it could possibly substitute for.

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I periodically encounter situations where I need to use a surface to edit a solid in order to create the geometry I need. In other words, the solid editing tools have limitations that can be overcome by using one or more surfaces. The exact nature of how I use the surfaces varies from case to case and nothing jumps out as being the most common. I will say that I have found cutting with surfaces to be particularly powerful when creating complex sheet metal parts. For some reason, SolidWorks sheet metal functionality is more versatile if you cut with surfaces rather than the other cutting methods. I discovered this after extensive trial and error.

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John Eric Voltin

You can move or angle the face of a solid. Nice for removing draft or actually modifying imported geometry.

I think this one requires that you understand how the brep works. You're basically asking SW to cover over faces with the underlying (untrimmed 4 sided nurbs) geometry of the original face.

Non-analytical faces are based on nurbs surfaces which are 4 sided, then trimmed to fit. This is how the Fill surface and the Shape command work, by making a 4 sided patch and trimming it to fit. the 4 sided surface is there in the background, almost like a feature history. Untrimming just reveals the base surface.

There's not a button for this one. You just select an open edge of a surface and hit delete. It will ask if you want to delete the feature or a hole.

It's the equivalent of move part in an assembly. SW06 will make this largely obsolete by using mates to position multibodies.

I guess what I'm wondering is why would you do it permanently? The only thing I can think is that SW handles solid bodies poorly, and things flow better if you only have a single solid body.

Instead of making a big sketch and cutting up to a surface, it's better if you can just cut with the surface directly. Sometimes you have to have multiple bodies and restrict the cut to a single body. Also. Replace face can add and/or remove material sometimes in the same way cut with surface removes it.

I've been just the opposite. I used up to body a few times on my most recent job. The way it colors the body is very distracting, and makes everything hard to see, like trying to read the print on a light bulb when it's turned on. Up to next does have some strange things that it does, but if you know to expect them, then its cool.

The ones to worry about are the end conditions and GC side tangency. Anything else I usually use defaults.

Great workaround for when a thicken won't work. Offset or copy a surface, then loft between the copy and the original. If that doesn't work then you need to build the side faces all the way around with a surface loft then knit.

I wish you could use a sketch, but it needs an edge.

Sorry for the typo. I meant when the ruled surface won't work, sometimes you can substitute a radiate.

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I've got to admit, that's new to me. Other than "lofted bends", I've never associated surfacing with sheetmetal. Do you have a sample part you could share that shows this technique? What types of cuts are you talking about?



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Thicken and Knit. Don't think they were on the list, but they would be a 9. In fact offset surface wasn't there and that is the basic means to get a copy of a face. I do recall some sort of surface option with shell as well. I think it happens when things go awry.

I've been working on large sprayed up concrete structures. Don't have to worry about draft but definitely freeform at times.

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Actually, it's not permanent. You can delete the "delete body" and your bodies are back again! I find it useful to semi-permanently hide the surfaces and bodies that you used to build the part, once you're finished with them.

Jerry Steiger Tripod Data Systems "take the garbage out, dear"

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Jerry Steiger

Oh boy, forgot one really big one. The Atomic Bomb of Fillets (E.E.'s nomeclature).

Take one overly complex intersection of edges. Extrude some simple geometry out from that intersection in order to consume it. Create fillets up to the extruded geometry. Use fill surface to "patch" the consumed area and terminations of the new fillets.. Use that surface again to trim away the extrustion.

This is not a single SW feature, but a combination of operations that pretty much guarantee's that SW can fillet any geometry. In fact it is conceivable that this method can join a fillet to a chamfer and a round to a fillet.

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One other issue.

Try to differentiate any operations with these that are documented in SW literature (Help, Training Manuals, KB, VAR communications, etc. ) from those cooked up solely by users. The reason is that SW will sometimes pull the undocumented feature lever when they take away a technique that we use just because it is not explicitly in the documentation. I attribute this to the fact that sometimes the people that define what SW is, are not aware of how SW is used. I'm talking about the programming level mostly because that is several levels of awareness away from the user.

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Right. What I'm wondering is why you would use this Delete Body feature to begin with other than just to eliminate the affects of multiple solid bodies (mainly SW miscalculating the feature scope, the blinding bright neon previews and the rib and mirror features always asking which body to add to). I haven't had the patience yet to test how it affects performance vs Hide Bodies.


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Good one. I just think of this as the Fill Surface, but you're right it does combine Split Line with Delete Face (or a solid cut).

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I can provide jpegs of the part (both bent and flat) or I can send a SolidWorks 2005 part file. Just contact me if you wish to receive any of this.

I'm not clear on what you want to know about the type of cuts I make. I should explain that I am cutting holes, notches, etc. on a lofted sheet metal part. I have noticed that lofted sheet metal parts don't allow very much further modification without introducing errors. Using surfaces to create cuts that you would expect to make with Extruded Cut produces results that are more likely to not have errors and still allow the part to be flattened. Looking at my sample will help clarify this.

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John Eric Voltin

Good discussion , Matt. My comments are in the same format as Paul's and Spork's.

4 - replace face (handy for adding or changing draft angles.)

3 - move face (sorry, but isn't this a solids function?)

7 - fill surface (real handy, but I am learning to try untrim first and only use fill when that doesn't work.)

9 - extend / trim surface (trim is really handy-especially the ability to trim with a sketch-Has anybody ever gotten extend to work when trying to extend up to another surface?)

7 - delete face (delete and patch, I consider a solids feature. I use that to take out a filleted edge sometimes so that I can apply a draft angle. Delete face is useful by itself, though.)

10 - untrim ( I love this for creating surfaces to be used in cavity/core creation.)

2 - delete hole (like delte and patch)

2 - move body (still learning when to use this.)

3 - delete body (only use this when I cannot decide which body to keep when an operation results in multis.)

10 - cut with surface (essential to mold design. I can't decide it it's more stable than the cavity feature-they both seem a little flaky when going back and making changes ahead of it in the feature tree.)

9 - up to surface end condition

0 - up to body end condition (I usually use `up-to-next, but need to learn more about this one.)

6 - loft surface (this one helps when creating complex parting lines. I need to learn more about ruled surfaces because that may be a better choice of tools for many cases.)

0 - loft a solid between surface bodies (never had occasion to try this.)

0 - ruled surface (never had one work-I must be using it wrong.)

1 - radiate surface (seldom use-usually has unacceptable wrinkles.)

10- offset surface ( usually one of my first steps.)

9- thicken (often this is the last step when I am doing a lot of surfacing.)

10-knit (essential building block to thicken, but seems a bit flaky when trying to form a solid with it. Seems more stable to knit with forming a solid and then thickening.)


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In article , jk_spam- not says... ...

My apologies, yes, you're right. It goes in the category of features you can use to edit imports that don't get much press.

Good tip, I like that.

Sometimes, depends on if you're using the "same face" or "tangent" option. Tangent seems to make more stable faces, but doesn't join them well if you're trying to extend adjacent edges or an entire face.

The presentation I'm gearing up for is how solids and surfaces interact, and the Delete and Patch function is a great way to demonstrate how SW uses surfaces in the background to edit solids. Also, the Delete Face by itself is the way to go from a solid to a surface.

more like untrim, I think. I don't think this works on solids, only surface.

I like all of the different methods you can use. I can usually get it to give me something, but they're not always well made. I keep trying to report bugs on this because it would be great to see this feature mature.

I have a feeling this has a lot of function in common with the ruled surface. They seem to handle non-tangent corners differently.

Thanks for the input!


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