hi all

i often have something like this picture when i use fillet.
did someone know why it is happening ?






thanks
Laurent

Hi laurent - looks like the fillet engine had some difficulty trimming the fillet piece with the surrounding geometry.

When the fillet engine runs into trouble automatically processing some part of the fillet, it will usually spit out all the fillet surfaces that it was able to generate so far so that you can try to use those pieces to do something with them. Like in this case you can probably do a boolean difference using the fillet piece to get the end result that you want.

Are all those surface pieces joined to one another, or are they possibly separate surfaces that are just sitting next to one another and not joined?

Is your model at some very large or very small numeric scale in overall size?

Can you please post the 3DM model file along with your screenshot when you have a question about a particular situation like this? That then makes it possible to examine the actual structure of your model and to zoom in to it, look at it from different angles, try to repeat the problem, etc... none of which are easily possible by just looking at a screenshot alone.

- Michael

hi Michael

sure. here is the file. look at the "red" style part. It's not exactly the same but it reproduce it.
only one edge is affected by this "strange" fillet. all others edges react normally. It was the case with the first example.

i forget to say that in both cases, the fillet works ok if i apply it to all edges at the same time.

thanks for your quick reaction. i appreciate it.

Laurent

ps: do you know if there is a french community for MOI ? At the beginning it will be more easy for this kind of technicals words and logic.

@Laurent
Il y a déjà la partie francophone du forum en haut tout à droite de la page! (languages) :)

But for the technical answer Michael will be the best ;)

Plusieurs videos en français sont ici ;)
http://moiscript.weebly.com/

hi pilou

merci :)

Laurent

Hi Laurent - your object is quite small in numeric size - it's only about 0.1 units across at its largest dimension and then it looks like you're probably filleting some small piece of that so you must be using some particularly small fillet radius like around 0.0001 units or something similar to that?

That kind of small sized stuff can tend to cause additional problems - I'd generally recommend not using fillet sizes below 0.02 units or so. Some areas of MoI target an accuracy of 0.001 for the results of operations that involve approximating curves to some tolerance, and if the entire surface that you are dealing with is also right in that same size range it will cause some confusion in the algorithms.

So for an object like this it's better to have the whole object at a much larger numeric size, probably 100 times larger than what you have here currently. So for example use centimeter units for an object like this rather than meters as your overall unit system. That will then give you numbers that are not so small.

I can't verify that solves your particular problem because I'm not really sure which particular edge of the model you were trying to fillet, the 3DM file that you posted had a lot of objects in it and was zoomed out to look at all of them so I can't tell which particular edge of which particular object you were having problems with.

But if you are typically creating things at this small of a numeric scale then that is likely causing you additional problems - if you switch to centimeter units and target numbers that are more in a range of say 10 or 100 for the full object size and down to 0.1 or so for the small features that will tend to work a lot better.

- Michael

Michael

you are right about the size of the fillet i was trying to make.
Thanks for the tip about modeling at a bigger size. I work with modo as polygonal modeler and this it the opposite. it's better to model to real world scale.
Just so you can have a look if you need i join a picture of the part that is causing trouble for the file i uploaded before






Laurent

ps: i just try with unity as centimeters but result is the same. i'll give it another try tomorrow. Thank you very much for your support :)

Hi Laurent,

> ps: i just try with unity as centimeters but result is the same.
> i'll give it another try tomorrow. Thank you very much for
> your support :)

It can happen that after initially creating things at a small scale that just scaling that same geometry up larger will bring some problems with it because when you scale objects up the small gaps between things also increase in size as well.

It looks like in this case the ends of that particular shape were just slightly non-planar and that amount of non-planarity will get increased when scaled up.

I've attached here a version where I have tuned up the piece by flattening the ends of the scaled up top and bottom surfaces to be all completely planar as it seems like you want (I did this using "Flat" snap using the edit frame from the Top view, that's when you squish the edit frame down in one direction there is a "flat" snap that engages when it is completely squished down).

3DM file is attached and this version appears to fillet ok now:





- Michael

re: modeling at a bigger size - just a note on that, it can also not be too good to create things at a really big size as well, like 100000 units across your object as well.

For that case the reverse problem happens and instead of the fitting tolerance being too loose the fitting tolerance can be too tight in relation to the object and generate overly dense results. When that happens it makes for large file sizes and slower calculation times.

I am trying to move more of MoI to a "relative tolerance" method where instead of targeting a fixed tolerance value it instead uses a fraction of the object's size as the tolerance. That can help make things adapt to either large or small sized objects better.

But that is kind of an ongoing process moving pieces over at a time to use that system, right now some things use it and some things don't, so it tends to be best to build things more in the size of maybe around 1 to 1000 units in numeric size (just the numbers themselves are what matters, not what the unit system is, the unit system is just a label).

- Michael

Would it be best to model in real world scales?? I know Vray works best when using real world scales.

Peace,
Rich_Art. ;-)

Hi Rich_Art,

> Would it be best to model in real world scales?? I know
> Vray works best when using real world scales.

The best thing for MoI is to model at a scale that avoids either too large or too small numeric values.

It doesn't really matter what physical scale it's at, you want to avoid doing things like generating fillets that use a radius of 0.00001 units. It doesn't matter if the units are miles, or millimeters, it's that large or small numeric value itself that you don't want to use.

So if your object has very large or very small numeric values in its real world scale then you would not want to use real world scale for that particular model.

But for a lot of things the real world scale that you would typically use can be good - like things of the size that you might find on your desk you would probably in the real world measure with centimeter units and that will yield not too large or small numeric values so that's good.

If you start to see numbers that you're trying to use that have a whole bunch of zeros in them on either side of the decimal point, then that's the kind of thing that you want to avoid and you want to work with such things at a scale where you're seeing numbers more like 50.2 rather than 0.000000052

-Michael

hi all

Michael : i quickly tried what you said with no result. this is the workflow i don't get. what are the different step to accomplish what you said ?
sorry for so many basics questions. i learn very slowly :)
can you point me where are the informations about the edit frame. for example when i tried to squish it until i see the "snap" and i want to go back to the original position i can't snap to it. i have to undo to have the original back.
i have to go for now, i'll come back tonight for more test.

thanks again
Laurent

@Laurent
Le cadre de Modification (Edit Frame) doit être coché dans le Menu Options/ View
Il suffit ensuite de cliquer à répétition sur l'un des 4 angles pour choisir son axe de référence par rapport auquel la modification va avoir lieue
(milieu ou extrémité)
De se mettre dans la vue concernée, et de prendre un de ces angles et le déplacer
Quand l'item Flat (Plat) apparaît tous les points sont aplatis sur l'axe choisi ;)
Suivant les "Snaps" souhaités il peut être bon de décocher l'accroche à la grille, aux axes, ou aux objets
Oui on ne peut revenir facilement, sur la position de départ, on le relâche n'importe où et un simple Undo ou CTRL + Z fera l'affaire ! :)

L'utilisation du cadre de déformation n'est pas toujours pertinent!
Il vaut mieux par exemple s'il on veut allonger une forme par rapport à une autre utiliser l'outil Scale (Taille) 1D
Comme cela on pourra utiliser les lignes d'aide pour se caler sur un objet à une position quelconque!
Un fois la fonction chosie (ici Taille) Les lignes d'aide peuvent se dessiner avant le premier clic, après le premier clic et avant le dernier clic !

Hi Laurent,

> can you point me where are the informations about the edit frame.

Check here:
http://moi3d.com/2.0/docs/moi_command_reference11_French.htm#editframe

There's a lot of information like this covered in the help file reference section, Pilou even made a translation into French!

The reference section of the help file is here:
http://moi3d.com/2.0/docs/moi_command_reference_French.htm


> what are the different step to accomplish what you said ?

It went like this - I changed the units to centimeters and focused on this object here:



I deleted the side wall parts, leaving only the top and bottom surfaces:



I had previously tried to build a planar surface by drawing in some new lines between the corners but that failed, which indicates that the ends of those surfaces are not fully planar with one another.

So one way to fix that is to turn on surface control points (Edit > Show pts), and select these control points:



Then switch to the top view which will look like this:



Now it is possible to edit those points to flatten them down to all be on one exact same plane rather than having them kind of slightly jittered around like they were previously. To do that grab the corner grip of the edit frame (the edit frame are the corner grips that show up around the current selection that allow you to scale or rotate it):



And then drag that down to flatten the frame, there will be a "flat" snap that engages at the collapsed point, like this:



If you don't get any flat snap then it means that it was already totally flat. But your object here was not, that's one of the things that was likely causing some of the fillet problems too.


> for example when i tried to squish it until i see the "snap"
> and i want to go back to the original position i can't snap to
> it. i have to undo to have the original back.

Sorry, I'm not really understanding this part.

If you drag something to move it, it is normal that you don't have a snap available at it's old previous position, if that old position was just out in space somewhere with nothing there anymore.

If you want to get back to some spot later on you generally need to place something there to serve as a marker, a point object can work well for that (Draw curve > More > Point).

Hope this helps!

- Michael

Thanks Michael.
I never use large/small numbers. Mostly between 10 and 100.

Peace,
Rich_Art. ;-)

merci Pilou :)

Michael : i was trying to do the manipulation with the object as a solid. that's why i was having troubles.
we can "only" show points for surfaces and curves ?
it works as expected now :)

again i want to thank you for your support since i'm not even a customer for now, but i sure will be very soon, no more doubts.

Laurent

@Laurent
Présentement on ne peut voir que les points de contrôle de tout objets, volumes surfaces et courbes!
Et évidemment les points chauds quand on passe dessus!

Hi Laurent,

> Michael : i was trying to do the manipulation with the
> object as a solid. that's why i was having troubles.
> we can "only" show points for surfaces and curves ? <...>

Yup, that's correct, except in special cases like with a box solid, since for a simple box case every surface inside the box shares control point locations with every other surface.

In most solids the surface control points do not necessarily align with one another at common edges - that's because edges are often formed by boolean operations which means that they are trim curves that are marking areas of a surface as holes or cut away parts.

Basically when you do a boolean operation in MoI, the full underlying surface does not change, it stays the same and only new trim curves are calculated on it. This is one of the main reasons why booleans work so much better with NURBS than with polygons, because polygons become fragmented into more and more little pieces with each boolean, while NURBS surfaces still stay in large sheets after each boolean.

But on the other hand the NURBS structure using an "underlying surface" and trim curves also means that there is not necessarily control points to edit at just any edge where 2 surfaces are joined to one another. That's because control points belong to the underlying surface and not edges, except in the special case where you have an "untrimmed" surface.

See this FAQ answer for some more description and examples of this issue:

http://moi3d.com/wiki/QUESTIONS_FREQUENTES#Q:_Pourquoi_.22Voir_Points.22_marche_pour_certains_objets_mais_pas_pour_d.27autres.3F


> again i want to thank you for your support since i'm
> not even a customer for now, but i sure will be very
> soon, no more doubts.

No problem, you're welcome! And from the look of your model it seems that you are already making great progress constructing things in MoI - if you just switch to work at not such a small scale you should likely avoid a lot of problems.

- Michael