Hi Petr,

re: Silhouette

> This new command doesn't seem to be very reliable... Also
> note that it generates incomplete or no result when using
> it on solid primitives (cylinder, cone; box).

Actually, what you show there in the screenshot looks to be the correct and current expected result.

Right now the Silhouette command does not create duplicates of edges that are silhouettes, it only calculates "brand new" silhouettes that are internal pieces of curved surfaces.

The reason why is to avoid making duplicate curves when using it for AI format export.

The way AI export works, is it exports all curves and edges in the model as curves in the flattened AI file. If silhouette generated copies of edges in addition to the internal silhouettes, it would make it pretty easy to get duplicate curves if you just did a SaveAs to AI format.

I can probably put in an option for whether to duplicate edges that are silhouettes or not though, would that be useful for you? I don't think that it would do anything useful for AI export though so probably that option would be off by default.

- Michael

Hi BurrMan,

Yes I get the illustrator stuff, but I'm sure I can use it for other stuffs, like a quick way to add sci-fi details using silhouette as sweep rails etc ;)

Hi PaQ,

> Not really sure what's the silouhette purpose, but I'll find :)
> (get same kind of result that tyglik is talking about)

It's mainly for helping to get better export to AI format to 2D illustration programs.

Since it will be a while before there is a complete hidden-line vector generation in MoI I wanted to get this function in there to help out in the meantime.

For example if you export a cylinder to AI format, it exports existing edges in the model, so that means your AI file for a cylinder looks like this (this was done by drawing a cylinder, exporting to AI and then opening the AI file back into MoI):



So notice there that having only the model edges in the 2D output does not make for a very proper 2D illustration.

However, if you use the new Silhouette command on the cylinder first, it will generate the silhouettes on the curved parts of the cylinder. Then when you save to AI format after that (without moving the view in between silhouette generation and saving!) it will produce a 2D drawing like this:




That's still not a completely proper 2D drawing, you've got the seam edge in there which you probably don't want and it does not have things broken down into hidden and visible portions. But it is a major step forward because at least it has all the "raw parts" of the drawing in there so you have stuff to work with.


> As the V2 beta cycle nearly end, I suppose surface continuity
> options will be 'only' added in the V3 ?

Yeah those tend to be finicky things to work with, it is not going to be possible to have that included for v2 other than where it already exists like for Fillet and Blend.

- Michael

EDIT: looks like we posted at the same time!

But there seems to be some general questions from many people about what silhouette is for, so I wanted to have a more full explanation here with some examples anyway.

Hi Marc,

> As Petr mentioned, the silhouette feature doesn't seem to
> work in the 3d view.
> It appears to be working ok in orthogonal views though.

Actually it was working correctly in the screenshot that Petr showed there.

It does not currently try to duplicate edge curves that are also silhouettes, it only generates "new" silhouettes for the internal parts of curved surfaces.

See this previous post for a better description:
http://moi3d.com/forum/index.php?webtag=MOI&msg=3000.18

If you do have an example where it is not working in the 3D view, could you please post it?

- Michael

Hi Burr,

> The silouette command seems to not like "Sharp Edges" at
> this point. It will perform on smoothed silouettes.

Yeah the part that seems to be confusing people is that it does not attempt to duplicate edge curves that are also silhouettes.

That's because all edges of a solid are already being written to an AI file if you do a "SaveAs" to AI format.

So if the Silhouette command added in curves that were duplicates of existing edges, it would be pretty easy for someone to end up with duplicate stacked up curves in their AI file.

But it sounds like I should probably put in an option for whether to extract silhouette edge curves also or not, that should be pretty easy to do.

- Michael

Hi PaQ,

> Yes I get the illustrator stuff, but I'm sure I can use it for
> other stuffs, like a quick way to add sci-fi details using
> silhouette as sweep rails etc ;)

Yeah the main purpose is Illustrator export, but maybe it could come in handy for generating a bunch of curves along a surface for other purposes.

The curves can tend to be somewhat chaotic in their actual 3D shape though.

- Michael

Hi Michael,

I guess I did not understand it was meant to complement the AI export mechanism results.
I think I get it now, I will try this!

Maybe it could have been included directly in the AI Export command when solids are selected?

Very cool to have the camera angle adjustment in perspective!!

Marc

Hi Marc,

> Maybe it could have been automatically included directly
> in the AI Export command when solids are selected?

I've thought some about that, but there are a few complications.

First of all, silhouette generation on a complex model can be a somewhat time consuming process so it needs to be able to be canceled. Things that are like that tend to be more technically difficult for me to incorporate into the saving mechanism rather than having it as a separate command. So it would take me additional development time to make that happen.

Also there are actually some other uses for silhouette generation such as generating parting lines for mold making.

Finally, I'm still just not completely sure yet about how the UI for a full hidden line generation should be structured. I have some idea that there probably needs to be a process where you generate a line drawing and get to see it and possibly edit it in a special 2D "printed page" type display rather than only having it baked directly in to AI export.

- Michael

Hi Michael,

Thanks for the new beta!

>V2 is very close to being wrapped up, but I still have a little bit
>of work left for Sweep (for mitered corners) and probably Groups
>before it is all ready so there will still be at least one more beta
>to come after this one.

This is the bit that really interests me. Looking forward to groups if you can get it done.

Hi Michael,

Can't wait to give this beta a whirl!

> Also there are actually some other
> uses for silhouette generation such
> as generating parting lines for mold making.

Exactly what we use it for in our industry, maybe I could post an example.

Cheers

Hi Marc,

> Very cool to have the camera angle adjustment in perspective!!

I'm glad you like it!

Also one additional note on this - if you want to change the default field of view angle that is used for startup you can do that by setting up a file that has the view how you want in it and then specifying that file as the startup template under Options > General > Template file.

- Michael

Hi Michael,

Thanks for the silhouette clarification !

Hello,

With this last update you have shaved several days off my current quick start guide project with the inclusion of the silhouette command, which is already paying off big after a few tests. Once I figure out how to fix my camera in one spot and at the proper angle I'll be set. Is it me or did you also optimize the overall speed of MoI in this last update? It could also be that I'm geeking out a bit over all the time I'm saving by being able to go from MoI to AI with no intermediate. Thanks again for the great update.

Hi OSTexo, that's great news, I'm really glad that Silhouette will be useful for your illustration work!

I was hoping to give a boost in that area with something sooner rather than only waiting to have a full blown hidden line system.


> Is it me or did you also optimize the overall
> speed of MoI in this last update?

Probably just enthusiasm at having silhouettes now... :)

- Michael

Hello,

Quick Test SMA-Male:

Modeled in MoI with plan reference, simplified (ex. not true screw thread), silhouette command, 15 minute cleanup in CDX3, saved as CDR and GIF for posting. One hour time savings alone over the conventional way, not to mention vastly superior point and curve output, easier cleanup, no smoothing required.

Hi OSTexo, that is awesome!

In MoI v3 I would like to make an attack on that 15 minute cleanup step as well!

- Michael

Hello,

Even Quicker Test GSM Low Gain Antenna:

I took measurements from an actual antenna using calipers, modeled it in MoI. I was looking for problems with the silhouette in the curved parts at the base of the antenna and around the input of the cable to the base. Passed with flying colors, I can't tell you how much tweaking time this new feature has saved me on this part in particular.

Hello,

Test Widget 001:

I've found MoI is exceptionally detailed in the silhouette / AI export command and will render absolutely every curve. When cleaning up it might be helpful to greatly increase the size of the image while decreasing the size of the outline to a hair to clean up all the stray lines that need to be removed. Two minute model, 10 minute cleanup.

Hi Michael,

>>Right now the Silhouette command does not create duplicates of edges that are silhouettes

Ok. That's true, but only with some View option. For instance, it produces a couple of "duplicated curves" on edges of simple box in case of View:Top option. Yes, the curves are actually in the different height, but only until exporting to AI...

>>The way AI export works, is it exports all curves and edges in the model as curves in the flattened AI file.

When using Export command? Nope. You have to use SaveAs command to export all curves and edges to AI. But I think the natural way to save only a part of object (e.g. outline) is using Export command and not SaveAs one. Especially, when there are selected curves after finishing Silhouette command and you "can't" manipulate the viewport without destroying the proper silhouette.


>>it would make it pretty easy to get duplicate curves if you just did a SaveAs to AI format.

Yes. On the other hand it is pretty easy to get "no" curves if you just do an Export to AI format.


>>I can probably put in an option for whether to duplicate edges that are silhouettes or not though

I guess it would be possible to just select all edges that are silhouettes and add them to the selection after Silhouette command finishes. After that it would be clear what curve/edge is intended to be exported to the AI file (and there will be no duplicated curve objects).



Well, I have rarely been satisfied with result of Silhouette command in Rhino as well. Maybe I have never fully understood the essential difference among the meaning of words: outline, silhouette, contour or boundary when talking about CG :)

I would expect these results doing silhouette:



...and optionally with hidden line detection (different line style or color or Style) in the future.

Petr

Hi Petr,

> For instance, it produces a couple of "duplicated curves"
> on edges of simple box in case of View:Top option. Yes, the
> curves are actually in the different height, but only until
> exporting to AI...

Yeah I saw that in a few cases - it seems to get slightly confused when a plane is exactly edge-on to an ortho view direction and ends up tracing the edges of those vertical planes as silhouettes.

I could probably screen those out, are they causing you a problem?


> When using Export command?

Sorry, I didn't mean the "Export" command specifically here, I was just referring more to general file I/O meaning writing a file out from MoI.


> Yes. On the other hand it is pretty easy to get "no" curves
> if you just do an Export to AI format.

Sorry, I'm not following this one - if you have nothing selected when you do an Export, it will prompt you to select objects before continuing.


> I would expect these results doing silhouette:

Well for example the edge that I've got outlined in red here is not a silhouette because both of the faces connected to it are forward facing.



A silhouette edge would be an edge where it is either connected to only a single face, or when connected to 2 faces one of them is forward facing and the other is backwards facing. That edge above would be a "visible" edge in a hidden-line removal drawing. But doing a full hidden line removal method is a lot more involved and complex than just silhouette generation.

This new Silhouette command just makes silhouettes and does not compute visibility stuff.


This one that you show here:



Is also probably not really feasible for this command, silhouettes are generated more at an individual face level so it does not know how to treat the "most forward" face differently from the "most behind" one like you are showing here. That would again be something that could be done with a much more involved hidden/visible line calculation instead.

- Michael