Solid vs Surface modeling

[2ms1]

I understand that a characteristic of Wildfire is that it has the older surface modeling style capabilities while also having solid modeling capabilities.


So far, for what I've done (as a relatively inexperienced user), surface modeling has made possible a lot of things that woudln't have been possible with only solid modeling.


Could someone explain what the benefits of the advent of solid modeling were when only surface modeling had been available previously?

 

[design-engine]

your opening a long discussion. Basically your options for modification are more wide for starting with robust curves and surfaces just look at those curves to form later solid geometry. One thing you can bank on is that surfaces pay better.

These answeres are only clear thru examples. The best way to understand those things you inquire about is from hind site experience. That may be rhetorical but ... Basically we could try to explain with words but the words only make since thru Pro/E examples.

Edited by: design-engine

 

[2ms1]

I'll accept that the explanation probably mostly escapes descriptionby posts on a forum. Butplease note that(at least I think) what you've basically said here otherwise was kind ofjust an elaboration of something I said I already understood - reasons why surface modeling so much better for lot of things. So that part of things isn't what I'm looking for greater understanding of.


WhatI was wondering was basically why solid modeling was invented when surface modeling already existed. That this happened means that there is something that solid modeling is better approach for than surface modeling.


Do you think there's any chance of being able to give idea of what solid modeling especially good at? Or is this only minimally different beginning of same long discussion that probably ultimately not very productive?

 

[design-engine]

that is a good question. Catia was always a surface modeler along with many other programs prior to 1993

CADS4x
CATIA
Alias

Others had solids modelers but they were not parametric. They did silly things like boolean operations. Problems like coincident surfaces existed.

1 With solid modelers engineers could easily export to mesh'ers for FEA or CFD analysis. I think the big thing was the ability that came around 1998 when PTC released Pro/ENGINEER the mind shift from looking thru layers of lines and trying to see an interference. 2 I explain to the 2d people going to Pro/E that 40 percent of my mental hoursepower was expended trying to understand what I was actually looking at 'thru all the lines'. 3 With 3d Pro/E My cross section told me exactly what I was looking at. I became smarter and products making to market fit together better. You simply could not cut a cross section thru parts in an assembly prior to 1988. It is amazing to me that it took some companies close to 20 years to make a move to 3d. How can they compete? 4 did I mention drawings were free with the views ect.... The drawing just updates. Autocad people are stills surprised as to how easy it is to update drawings in Pro/E. Hidden line removal in AutoCAD 3d in 1988 was an ugly undertaking and most did not even bother. 5. Assembly mode was a new one. Some programmer sat and thought to himself. 'if I has subrutines and can modify those independently of the whole why cant I have parts that update inside assemblies. WOW we went thru the 80's w/o parametric solids modeling I don't know.... but NATO won WWII with paper and pencil.

with respect to surface modeling... most persons out there are doing conveyors for bottles not bottles. most engineers are pushing paper not running proe too but for most people don't do complex forms just complex assemblies. Those things require only extrudes and revolves.


Edited by: design-engine

 

[muadib3d]

I saw what CP and design-engine do and did in/with surfaces and this is amazing

I wish I would have those skills to play with surfs as they do

but as far as I am concerned with my job that has nothing to do with car interior or advanced, anatomical shape at all, I am far away from digging surf and using them as a basic and only tool

I think the statement what is better does not feet to this case. It all depends on what is Your point of interest. So basicaly I spent last 4.5 year working in R&D for automotive industry focused on air brake system for trucks.

Scope - valves. What was mainly used? Solids! Surfs only for cavities, cores etc.
It was hardly to play with surf through whole model, because the demands for pro\e models were high:

-use dims in model to show them in drawing(exact the same)
-be able to suppress all rounds and drafts
-make easy and clear to understanding model for others
-create less relatioship as possible
-no external refs(almost)
-etc

Through all this time I was confused if surfs fit better? But no, not in this type of models. Only in the small scale.

My final opinion is : as far as You are not pushed to make model with exact dims as will be shown in drawing and you face anatomical shapes, strange ones - use surf

if You have common industry shapes one can noticed in devices like valves, solid fits better

btw - last half of year is my new challange in new company, Audio/Video this time. I am involved in LCD TV project. I thought I would do all in surf, but it stucked in half of way. I decided to build core geom in surfs and the rest, many small details in solid, because it is easier.

piece of this adventure one can read in this topic - http://www.mcadcentral.com/proe/forum/forum_posts.asp?TID=33 379&PN=0&TPN=1

 

[ddrichards]

This might be slightly off the subject, but I'll throw it in. Sadly, most of the places I've been refuse to consider the benefits of surfacing, even hybrid modeling is rejected by many who simply don't understand or know better. The average user out here seems to believe that surfaces have no benefit, you can probably do it with solids, and that people that use surfaces are only wasting time and effort only to feel superior. I haveseen some models where the last part appeared to be true, but thesurfacing wasn't done very well either.The above doesn't reflect the opinions of the author.

 

[james.lynch]

well, I work in Consumer Product Design and simply could not do my job without surfacing - ever have a go at creating a mouse using solid modeling techniques?

in fact - I would go so far as to say that 90% of my models remain as surface models! (we use a master surfacemodel technique)


Even for those of you who create plastic bexes - howdo yo add a "valley" around a boss to remove sink mark if it cannot be done by sweep or revolve?


Just my $0.02


James

 

[prohammy]

And just to throw a load of aviation fuel on to this smouldering match...


Metal = Solid Modelling

Plastic = Surfacing

Kev


Boy, can I generalise or what. I should be in politics

 

[2ms1]

Yeah, to me it's obvious why surface modeling is necessary and/or preferable for many things.


What I am still a bit unclear on are the pros of solid modeling. That is, whatthings solid modeling excels at relative to surface modeling.

 

[muadib3d]

well, what you do not have to do in solids:

1)you do not have to make mergers and pay attention of sequence while merging surfs to have right normal direction
2)You have less feat count
3)you have less feat relationships
4)Pro\E shows You automaticaly all edges which creates solid closed geom
5)You can pattern and copy directly featerus, not their surf copies
6)you have less problems with patterning feats in solids, pattern for merges are still confusig me
7)You have more clear model view without using layers to hide unnecessary feats
8)etc

what you do not have with solids

1)boolean operations are forbiden for solids in Pro\e
2)You can not have a impact for normal of created surf
3)you can not make complicated shapes with small amount of feats
4)Yoi have to use shell or thicken revolve extrude to create thin walls which does not allow you to play with direction of added material
5)you would not be able to solve some draft - round problems with solids, because Pro\e fails in mergenig surf for round some times
6)solids regenerate longer and creates "heavier: geom
7)solids are bad for "construction" elements because they have impact in mass
8) solids featrs can not be hidden by layer in part mode
9)etc

so summarizing this - You create easy shapes like housing for valves - use solids, and surf for complicated cavities or patterns for big groups

You are creating complicated shapes, big models like engine block housing - make it as surf first then solidify it in another part to make it less to regenerate

 

[magneplanar]

2ms1,

It appears there is some argument about the validity of each modeling approach, when in actuallity it should be seen as options for you to enhance your capability. Apply the use of a surface or a solid when those methods make sense and allow you to complete the task in a reasonable timeframe. Challenge yourself to enhance your abilities so you can apply the right tool for the job.

If the concern is when to use which method then consider which one are you capable to use? If you find your surfacing is weak then stick with solids and build up your surfacing. It can help you alot to build models that are satisfactory as solids using all surfaces. In the end we do this kind of work for our employment so our modeling technique should provide robust, well thought out, adaptable models on time no matter what the product. It can only benefit you to be proficient in as many tools and techniques as you can even if all you make is nuts and bolts.

cheers,

M

 

[2ms1]

oh yes absolutely I want to get as proficient as possible with both


muadib3d, thanks for the detailed rundown. That was pretty much exactly the kind of answer I was hoping to get.

 

[Zaki]

Hi Guys


there is a good news for everyone. You can get more complex shapes then surfaces within one feature, WARP. both ptc and catia make it happen. We mostly dont use it. Just use its sclupting capabilities and you will 70% forget surfaces.

 

[Zaki]

just like this


View attachment 3606


View attachment 3607


View attachment 3608





just 4 features make this part, Protrusion, warp and 2 rounds.

 

[design-engine]

warp needs some improvement before it can be taken seriously.

 

[james.lynch]

hmm.... I think warp ismany generations away from where it needs to be for production - it's a good concept modeling tool tho'.. ie. what would this shape look like if it was 10% shorter or whatever...


James

 

[design-engine]

the industrial designers at design engine are and should be picky. Warp does not give a designer the control as say CV manipulations. Now thats what we get in WF4.0 ISDX. How is the weather james in england?

I am going to plan a trip thru england for next spring. I will try to speak at the Warick Pro/E user conference and make my way thru a hand full of schools to conduct free workshops to engineers. You up to meet up?

 

[james.lynch]

WF 4.0 is sounding pretty good (for surfacing anyway! - keep up the great work Tim!)


Hmm.. england... I know one or two Irish people who'd be more than a little peeved to be called english, Luckily I'm not one of them!

The weather has been pretty sweet actually! if you're actualy interested..


The dominant influence on Ireland's climate is the Atlantic Ocean. Consequently, Ireland does not suffer from the extremes of temperature experienced by many other countries at similar latitude.





Average annual temperature is about 9

 

[design-engine]

I can now read. IRISH nice. I wonder if it is the same as in the states.. you have the south who hates people from the north. southerners talk funny.


Edited by: design-engine

 

[james.lynch]

I wonder if it is the same as in the states.. you have the south who hates people from the north.

Bart if you only knew!

"The Troubles consisted of about 30 years of repeated acts of intense violence between elements of Northern Ireland's nationalist community (principally Roman Catholic) and unionist community (principally Protestant). The conflict was caused by the disputed status of Northern Ireland within the United Kingdom and the domination of the minority nationalist community, and alleged discrimination against them, by the unionist majority. The violence was characterised by the armed campaigns of paramilitary groups. Most notable of these was the <A title="Provisional IRA campaign 1969