Geometry Check

[zimmy]

Hi folks !

I'd like to better understand the meaning of "Geometry check" info.

Anybody knows where it's possible to get info, docs, examples about it ?

Thanx in advance



Pier

 

[muadib3d]

Well if You find one - please put it here

Geometry Check is a tool inside pro\E which chceck the existing geometry if it contains errors.

That question is : what the errors are?

Some of them are just copy of list of errors included in german automotive norm - VDA 4955(as far as I remember)

So those are all things which could exist in geometry and cause big problems in :

*FEM analisys
*manufactring
*data exchange

some most unwanted ones are:

*manifold geom
*surfaces intersecting each other
*the surf is very close to but not touching
*and a lot of more which I do not remember

So in real Geom Chceck is not able to solve any problem, it is only an info. You personaly have to deal with them by changing the dim of features that cause a problem

What are common ways to deal with geom checks? Read this:

*change the sequence of feature
*try to be carefull with using edges as ref in sketches
*try to change dims to avoid problematic elements like - short edges
*divide big sketchers into smaller ones, it will help You to play with right sequence
*generaly, if it is possible - try to divide your model tree on first all features that creates external geom, second all feats that creates inner geom
*and in addition try to first add a material, than make a cuts
*and in the end - set up absolute geom

uff... I think this kind of info should spot a little light on this topic

 

[sanjeevkar1]

everything you said is fine but the problem i am facing is: my models do not sho any geom check till i add drafts and rounds. the moment i start putting drafts and rounds. the error ocurs. anyway out for this?

 

[muadib3d]

so first type what kind of geom check You have - I can not read in others minds yet))

but I supposed You have - short edges, surf is close to but not touching?

so then, it is sad, but You only can change the dim for draft or round, or change the rounds to quilt and built them with merging with other surf then solidify

You can also put some drafts directly to sketchers - specialy for revolved surf

many ways - but remmember - if You already creates the geometry form 2d existing drawing, everything is possble with pencil and line, but not in ProE.

Pro\e is to accurate for this

 

[eddie]

everything you said is fine but the problem i am facing is: my models do not sho any geom check till i add drafts and rounds. the moment i start putting drafts and rounds. the error ocurs. anyway out for this?

Try changing the model accuracy tosolve radius and draft features that cause geom checks.

 

[muadib3d]

yes that is right, good that eddie noted that

thanks

so it is better to start with the absolute. This kind of accuracy can make regeneration faster and could also help manufactring and DMU creation in assembly

 

[zimmy]

Just to better define what I ask.

I wonder which is the exact definition of Geometry Check.
It's possible to know some examples when this kind of problem comes out ?
It's depend on accuracy ?
How to manage these problems?
Are dangerous problems ?

Thanks again
Pier

 

[muadib3d]

Hi zimmy

For sure Geom Check could be dengerous, but it does not mean they mus to!

So the main unwanted geom check with solids are manifold problems, surf intersect each other, gaps and cavities.

It depend on accuracy - a lot. Some geom check are just tiny elements which YOu create without knowing about that. So usually they appear while cutting opertations.

Some of ways to solve this problem You can find in the previous topics.

But I can bet You want to have more detailed

Maybe - I say maybe - I will try to create a model with geomcheck and then show how to solve them. But I am not an expert of this kind of stuff. So all it would be just my experience

 

[Zaki]

Hy guys


actually whenever ur geometery makesthe mathamatics of curves and surfaces ambigiuos, pro shows error msgs and complete the feature. this kind of errors should be checked by info geometry check. Its like a surface or curve lost one of its portion due to draft or any other cut or round. Actualy now-a-days its so easy to make rounds. But upto Rel 20, the people says that "if a person is expert of rounds, he is expert of pro with no doubts". some times we make gemotries that can not fullfill math, but we makes copies from manaully produced parts so we face the problems. But If we understand exactly, we can overcome it by changing dims by some microns. I will post an example soon.

 

[Zaki]

Hy Guys


I am starting a new thread, "shell challange". Plz check the part, and make it shell with 2.3mm thickness. Its going to be failed, pin point the problem and solve it and tell us all. ( I actually did it, but for your information and practice, I put it here). Try hard every one.

 

[muadib3d]

where is the part Zaki?

btw - great idea!

 

[Zaki]

there is a new topic named "shell chellenge" I put part there.

 

[muadib3d]

ok, it was long break, but I promised I would do something in this thema

so I am back with some basc info about geom checks

here thet are



1) A side surface of this feature is very close to, but not
touching the highlighted edge.

Align the
highlighted entities to the highlighted vertices.

View attachment 3431

View attachment 3432

View attachment 3433
as You can see Pro\e highlight the sketch and place when the problem occur. In this case - sketch contains an element which is very close to existing edge. The change of sketch is necessary



2) This feature creates a tiny edge. The edge is highlighted on screen.

View attachment 3434

this case is a result of previous one. The elemnt in sketch cuts the existing edge and this cut is less or near the choosen accuracy. Solve first, this one will be solved automaticaly

3) The boundary of the highlighted surfaces was
extended. Unexpected results are possible. Try to modify the feature so that
extending is not necessary

View attachment 3435

in this case geom check is a result of merge feat. It happen that two surfs do not intersect entirely and pro\e has to make some new edges by its own. Solution - change the surf to intersect correctly or leave ti. It is not so bad geom check



4) The system could not construct the intersection of the
part and feature.

Redefine the
feature so that it intersects the part.View attachment 3436

View attachment 3437

View attachment 3438

in this case the surf for cut was made first. Then Solidify func was choosen and cut was done. But, the problem is the the surf is larger then required and intersect with another solids surfs. Pro\e made a cut as reqiured but it recognize also the intersecting problem with another surf. Change the orig cut surf

 

[muadib3d]

well dig it deeper with the last geom - The system could not construct the intersection
of the part and feature

another two cases:

1)solidify

View attachment 3454

View attachment 3455

cause of problem? - surf cuts another surf but not in whole lenght, in this case it is worth to make the solidify before round(if it exist), or change the cutting surf by extend func to not come close to another surf

2) round

View attachment 3456

in this case it is just example what could happen with rounds(one of many problems which could happen btw)

in general this can be solved by adding rounds with the same value at the front and at the bottom,

but lets imagine it is not allowed, so usually the best of the easiest ways to solve problems with drafts and round is right sequence - change the sequence of drafts and rounds and you will see how edge chain is changing. Badedge chain is main cause of round problem.

So we can assume that in this particular example changing the sequence is not enough either

Well, then, this can be done by using surfaces. This is how it could be done- make rib by surfaces, merge it, and create required round

View attachment 3457

make a round in the bottom, and solidify quilt - no geom check, no problem

View attachment 3458

this way contains to approaches - changing of sequence and surfs

 

[dmhuy89]

thanks so much but attachment files may be dead.please upload again muadb3d.thanksyou.a_a

 

[moldman]

I run into a lot of geometry checks in pro mold using imported parts for the reference model. In my experience if everything splits like it should and you get extracts then the geometry checks can be ignored.