need help with my hard-edge-car please!  1-20  21-28

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 From:  mike (MIOHN)
6449.1 
Hi,

I know that I'm doing something wrong here, but don't know
how to fix it or make it better.
I made this model in C4D for Layout before and now I need
an IGS-Model. (This will be produced as a "very small plastic/rubber model later)
So I hoped to quickly rebuilt this in MOI.

I got now the shape that I need, but cannot bevel the outer edges
and inner extrude the window-frames.

Surely because the faces or not planar and also the whole object is not closed/solid.

Any idear how to solve this?

thanks
Mike

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 From:  Michael Gibson
6449.2 In reply to 6449.1 
Hi Mike,

> I got now the shape that I need, but cannot bevel the outer edges
> and inner extrude the window-frames.

Which edges are you trying to bevel? All of them? Some of the juncture areas where you've got small edges from some slivery pieces will probably be difficult for the fillet engine to handle very well - it won't be able to fillet things if an entire edge or face would be consumed away by the bevel and you probably have several little edges where that would be the case unless you used a very small fillet radius. Also many of the junctures topology like with 7 or 8 edges all coming to a single point with all different angles between the different faces is a quite complex case to fillet, it makes for a difficult to form juncture patch where the fillets are coming together. In sharp edges things like that, the fillet surfaces will be of different widths and are hard to connect up.

Basically when you do a fillet it generates an arc of the particular radius you are asking for in between the surfaces. When the surfaces meet at a small angle it's a short arc that goes between them. When they meet at a big angle, an arc of the same radius is longer so the fillet is longer as well. MoI's fillet engine is not very good at dealing with the complex corner juncture cases that are formed by this kind of situation. You may have better luck in something like SolidWorks or ViaCAD for doing the fillets here.

For extrusion, you can extrude a face that is non-planar, but you may have to use the "Set dir" option on something like that to set the specific extrusion direction direction that you want to use. But extrusion in MoI means to take a curve or a face and produce a solid from it by moving it in one single direction. Maybe you mean something else which in MoI is called "offset" which is taking an outline and making a new shape that is a constant distance away from it?

If you want to offset the window frame edges, you would probably want to do that by duplicating the edges you have as regular curves (select them and do Ctrl+C / Ctrl+V), then take those curves and make them planar in the Top view, by grabbing the corner of the edit frame and using "flat snap" as shown here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=3378.4

You will then be able to offset that planar curve to make a sort of border thickeness shape, like this:






I'm not sure if I understand correctly what it is that you're trying to do with the windows though, if that's not it maybe you could explain it in a bit more detail.

- Michael

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 From:  Michael Gibson
6449.3 In reply to 6449.1 
Also I'm not sure if it produces the kind of border that you're looking for, but you can also try selecting your window face and running Construct > Offset > Inset. Similar to fillet it can tend to be difficult for it to work very well on complex topologies like you've got in this case, but it does seem to work ok on your window shape though. When you pick a border thickness it will build a result like this:





- Michael

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 From:  mike (MIOHN)
6449.4 In reply to 6449.3 
Hi Michael,

thanks for your reply!

The window frame you did is what I was looking for.
Maybe I will try to include the face behind as well.

I know, that I cannot fillet edges, where edges come extremely together like
in some corners. But I tried only some edges with enough space and that also did not work.

Can you try to bevel f.e. just the roof-top-edge.
A small bevel amount would be enough (just to break the hard edges a bit)
and maybe send me your file back?

thanks very much
Mike
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 From:  Michael Gibson
6449.5 In reply to 6449.4 
Hi Mike,

> But I tried only some edges with enough space and that also did not work.

Another thing that tends to make things difficult for filleting is having surfaces which are at very shallow angles to one another like only a 3 degree angle between them, rather than being either fully sharp or fully smooth. You've also got a fair amount of things like that in this model and so that's likely causing additional difficulties.

Very shallow angles between pieces tends to make for very small slivery and difficult to deal with juncture patches.


> Can you try to bevel f.e. just the roof-top-edge.
> A small bevel amount would be enough (just to break the hard edges a bit)
> and maybe send me your file back?

I'll take a look but I'm not particularly optimisitic about it, this model has a lot of things about it that make for difficulty with filleting.

- Michael
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 From:  mike (MIOHN)
6449.6 In reply to 6449.5 
Hi,

how would you recommend to model this kind of car in MOI?

What I did was drawing straight single lines (which snapped to the endpoints of the others)
and then build the faces one by one with "contruct" - network.

Is this the right way?
Have no idear, how I could it otherwise.

regards
Mike
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 From:  Michael Gibson
6449.7 In reply to 6449.4 
And yet another thing that's difficult for filleting is when you try to target only a portion of some set of sharp edges, making the fillet engine try to sort of simultaneously smooth some areas yet then collide into a sharp adajcent area.

Here's an example - here I've put in a surface/surface fillet in this spot:




If you then want the fillet to suddenly stop, it basically means there wants to be a hole created like this:




I also wasn't quite sure what you considered to be "roof-top-edge" - is it this:



Or is it this? :




Either one is probably going to have a lot of difficulties with filleting, it may be better to do an alternate type of rounding which is to slice away some area and use Construct > Blend to put in some smooth connecting surfaces rather than actual fillets.

I'm not entirely sure yet though - I'm not even quite sure what edges you want to smooth quite yet.

- Michael

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 From:  Michael Gibson
6449.8 In reply to 6449.6 
Hi mike,

> how would you recommend to model this kind of car in MOI?
>
> What I did was drawing straight single lines (which snapped to the endpoints of the others)
> and then build the faces one by one with "contruct" - network.

It tends to be better for things to be made out of a smaller number of larger smooth surfaces rather than lots of fragmented pieces.

But I guess in this case you are intentionally wanting a shape that has a lot of flat faces in it?

That then becomes very challenging to try and introduce some amount of smoothness later on though like you're trying to do.

Maybe you can get some pieces built with something like a loft between several polylines rather than just only doing a patchwork of 3 or 4 sided areas only.

It would help if I had a better idea of which particular area you were trying to smooth.

- Michael
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 From:  Mauro (M-DYNAMICS)
6449.9 In reply to 6449.6 
Hi Mike

This seems a typical sub-d workflow..you did this model in C4D right?
I think you know -Hypernurbs-tool in C4D:put your sharp low poly model as child of hypernurbs and you'll get a smooth rounded shape
Doing this in Nurbs need a different approach:draw contour lines and then choose which tool to use
As Michael says is not clear what you want to fillet and what not
better to post a hand-sketch ;)
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 From:  mike (MIOHN)
6449.10 In reply to 6449.9 
Hi Mauro,

in C4D it o.k. with Polymodelling.
Problem is, I need this thing in IGS-Format and C4D
cannot export or convert a Polymesh aa IGS.

regards
Mike


Michael, could you please post back the file you made?

thanks
Mike
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 From:  mike (MIOHN)
6449.11 In reply to 6449.7 
Hi Michael,


Well not all edges have to be beveled.

The second longer roof line looks good.
Maybe also one around the major silhouette arround the car
would be fine.

Btw. how did you get the bevel on the roof?
Which fillet-settings did you use?

On the other side:
When this thing will be produced in such a small size,
it gets beveled automatically I think.

thank very much!
I'm using MOI not very often - so everytime I start from
the beginning. Still learning.

Mike
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 From:  Michael Gibson
6449.12 In reply to 6449.10 
Hi Mike, here's a version saved off but it still needs more work to clean up the juncture areas where fillet pieces meet up.

These fillets were put in by doing a lower level surface/surface filleting - that's where you use Edit > Separate to break the model up into individual separate surfaces, and then select 2 of those surfaces at a time and then run Fillet. That can construct fillet segments for situations where the edge-based one can't figure out juncture areas. But it means the junctures have to be manually created by trimming and construction of some fill in pieces yourself.

I also used loft for some pieces to build a larger piece from one side across to the other to get rid of the additional edges running down the middle.

I'm still not entirely sure if this is actually the area that you wanted smoothing in or not.

There are some changes you could make to the body structure that would probably help with filleting - if the 2 roof top pieces that are at very slight angles to one another were instead made up of one large slightly curved surface instead that's probably better for filleting for example.

The least amount of fragmentation as far as number of edges and faces tends to be helpful.

- Michael

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 From:  Michael Gibson
6449.13 In reply to 6449.11 
Hi Mike, so here's a version where I've simplified the roof to be just one slightly curved piece rather than being made up of fragmented surfaces at very slight angles to one another (see attached 3DM file):




You'll still have problems with trying to do the whole roof all at once, because of the complex corner junctures, but you will now be able to do either the front/back or left/right set of edges alone now, like this for example:






- Michael

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 From:  mike (MIOHN)
6449.14 In reply to 6449.13 
thanks very much for your support!

Will go on trying with the method you descriped.

regards
Mikje
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 From:  mike (MIOHN)
6449.15 In reply to 6449.13 
Hi Michael,

apologize, if I have to bother you again!

Tried my second vehicle for Mini-Production.
This time I cannot export the object as IGS.

Maybe because I cannot get it to be a "solid"

I think MOI urgently need something like an "Optimize"-Command.

Even with "Object-Snapping" enabled and really paying attention when
drawing curves and making "network-faces", I very often notice, that,
when zooming very close, that corners/edges of the faces do not match and
have small gaps.

What can I do in such situations?
How do I get a "sold" Object?

thanks Mike
Attachments:

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 From:  Michael Gibson
6449.16 In reply to 6449.15 
Hi mike,

> Even with "Object-Snapping" enabled and really paying attention when
> drawing curves and making "network-faces", I very often notice, that,
> when zooming very close, that corners/edges of the faces do not match and
> have small gaps.
>
> What can I do in such situations?

It depends on the specific situation, it's actually not necessarily a problem, it's possible that you may be worried about something that's just a display artifact where an area of the display mesh just did not get refined with a lot of polygons, or it can also be normal that corners will not touch each other exactly and that's ok as long as they are within a tight enough tolerance of one another.

It's a normal part of a NURBS model that junctures where many edges come together will have the edges within some tolerance amount of the vertex, not necessarily each one ending exactly on it - many parts of NURBS modeling involves calculations of things like intersections and cuts to some acceptable tolerance level.

It's kind of hard to give you a very good answer without seeing a really specific situation...


> How do I get a "sold" Object?

I'll take a look at your model and see what might be wrong with it. But usually the best thing to do if you need a solid and your object is not a solid is to use the "select naked edges" script as shown here which will highlight edges that only belong to one surface instead of being joined between 2 surfaces:
http://moi3d.com/forum/index.php?webtag=MOI&msg=6051.2

- Michael
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 From:  Michael Gibson
6449.17 In reply to 6449.15 
Also it's normally ok to export non-solids to IGES format, IGES does support just surfaces alone. If you can't export it then maybe you're running into a bug in the export library, sometimes if there's certain kinds of malformed trimming boundaries the export library can trigger an error and bail out from doing the export. I'll take a look at your model now.

- Michael
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 From:  Michael Gibson
6449.18 In reply to 6449.15 
Hi mike,

> Tried my second vehicle for Mini-Production.
> This time I cannot export the object as IGS.

Over here I tested loading your attached 3DM model file and then doing a "Save As" into IGES format, which seemed to generate an IGES file ok.

Which version of MoI are you using, are you using v2? If so then I'd recommend using the current v3 beta instead, which you can get from here: http://moi3d.com/beta.htm

It looks like your main car body in this case is made up of 146 individual separate surfaces - these can be written to IGES format, but it is not a bad idea to use Edit > Join inside of MoI to glue together 2 surfaces that you intend should be adjacent to one another. That's generally the easiest way to test if they are actually meeting up closely enough or not, if they are too far apart from one another they won't join.

Also in some spots like here for example there seems to be a duplicated surface with 2 surfaces stacked on top of the same surface area, that's going to most likely cause problems in the receiving application:




It's also better in general to go about building the model using larger extended surfaces that then get trimmed to cut material away, rather than in a segmented "patch by patch" type method like you're currently doing. like the bottom part of the car body would be better if that was one single big surface that had a trim boundary on the outside of it to produce the outside outline, rather than a couple dozen separate pieces that are flat or nearly flat to one another.

- Michael

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 From:  Michael Gibson
6449.19 In reply to 6449.15 
Hi mike, another thing that you may run into with IGES format transfer, is that usually even when you have a solid IGES files are transferred using a collection of surfaces and then the receiving application rejoins those surfaces together to make a solid. Because of this it can be problematic to have multiple separate parts that touch each other contained all within the same IGES file. It may be possible for the receiving application to sort things out if you have put them on different levels (called "styles" in MoI), but that may not always be supported. So you may need to write out one file with the wheels for example and it may be problematic to have the front bumper which looks like it is a separate object to be in the same IGES file as the rest of the body.

What program are you trying to get this model into by using IGES format? You might try using STEP format instead, STEP is somewhat newer and is usually set up to work with solids so it can tend to avoid some of these issues.

- Michael
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 From:  mike (MIOHN)
6449.20 In reply to 6449.19 
Hi Michael,

I tried to "join" the faces several times. But it does not seem to work.
After the "join" command, when I click on the object, it only selects the part/face
where I clicked and not the whole object.

I will go through your posts and see, if it helps.

IGS is requested for production. Get feedback tomorrow, if other formats
are accepted.

I know, that my workflow is not the right one for nurbs modelling.
I come from Polymodelling and sculpting.

With "network"-faces I have massive problems.
When I'm just playing arround, I get the strangest shapes in MOI with
fillets and holes etc. etc.. Everthing seem to work well.
But as soon as I have to work on a concret object/shape (like this toycar) nothing works.
I cannot even bevel the simplest corner. Still have to learn a lot.

A complet car tutorial would be nice!
The ones I found are recorded are all without audio and
so fast, that I cannot follow, whats going on.


regards
Mike
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