> Pss Silly Question : After a Chamfer or a Filet of an object "Show Points" don't work!
> Is that normal? (I am a little tired with this winter / summer hours changes:)
> I must separate again for show it!

It's normal - it is a limitation of how NURBS work. You can only turn on points for an object with joined surfaces, if all the surfaces have the same control point structure along their common edges, and the common edges must be "natural edges" of the surface, not trimmed edges.

When you have a trimmed surface (which is the result after a chamfer or fillet operation), the control points of the underlying surface are different than the structure of the edge. This is what is really different between NURBS modeling and polygon modeling - in polygon modeling the edges you see are always the edges of the surfaces that are involved (they are one and the same). This is not always the case with NURBS modeling, here is an example:



Here the surface is a simple plane made up of 4 control points. The plane has a trim curve on it that trims away a portion of it. But the points that make up the trim curve don't define the surface, the surface is controlled just by the 4 surface points.

That's why in general you can't manipulate NURBS surfaces by dragging their edges as you would in a polygon modeling program - trimmed edges define regions of the surface but do not define the shape of the surface itself, if that makes any sense.

But on the other hand, this method of defining a surface is the reason why booleans with NURBS is so tremendously better than with polygons - every time you do a boolean or a trim, the surface stays exactly the same and just new trim curves are calculated. It's much more of a "nondestructive" type of operation. You can even recover the original surface by removing the trims later on if you wish. With polygon modelers, when you do a boolean it generates a tremendous number of new facets all over the place, the complexity of your object starts to increase dramatically.

So now imagine that I have another surface attached to the trim curve of that plane - for example an extrusion of the trim curve. This second surface has a totally different set of control points than the plane does. If I allowed you to turn on the points for such a joined set of surfaces, it would be really easy for you to grab one of the points and pull it such that it created a gap between what used to be a shared edge. This is why such point editing is not allowed, it is too easy for it to create gaps between shared edges.

Please let me know if any of this doesn't make sense.

This understanding of how trimmed surfaces work is really a key idea in understanding why NURBS modeling does not follow the same type of face/edge/point dragging as poly modelers. It's a very different structure and they have very different ways of working. Each way has its own particular strengths and weaknesses.

- Michael

> Have you seen the "how to make a church video" for the Arch looping?
> http://www.steph3d.net/Dossier/Ressources/TutsVideo/MoI-Archi.php

I saw it just briefly, I haven't had a chance to go through the steps myself yet. (By the way these videos are really cool, it's definitely easier to see them in Flash than using that special codec).

One thing I noticed - there is a portion where he moves some of the control points around.

One thing you kind of have to be careful of is to not move control points such that two points of a single smooth curve segment become stacked up exactly on top of each other. This sort of degrades the smoothness of the curve and it will probably cause problems for more advanced operations such as surface/surface intersection later on.


> Difference "hide" between Hexagon MoI is that you can "unhide" object one by one !
> Useful when you have a lot of object :)

I see. So when you go to unhide, it temporarily shows the hidden objects, lets you pick some of them and then only shows those particular ones, is that correct?

This would have a side effect of making unhide take an extra step. I'm a little worried that it might make it confusing for people who are just hiding a couple of objects. But I can see that it would make it much more powerful. I'll give it a try and see what it feels like after the mesh stuff is completed.

- Michael

> A new video for show that when you select many objects,
> that became more slowly! Not with the camera moves but
> when there is a "multiple selection" !

Ah I see - this is when doing a transformation, such as dragging.

Yeah, this area is quite a bit different than just the regular display such as when moving the camera, it will be possible to optimize this part quite a bit more in the future.

If he can post the model he was showing somewhere, it would be useful for me to use when I get a chance to work on this.

- Michael

As some people are interested to make architecture with your prog, ( dixit Steph),
it will a good thing to have the 6 classic views!
So just miss Back, Left, Bottom :)
It's not the normal use of a nurbs modeler but why not change that :)

> An undo / Redo for the selection :)
> When you select 50 lines(object)...if one miss all is to redo :D

This is on my list already. :) It will probably happen in a beta after image planes and arrays are implemented.


> Another thing : here bottom windows are "reclosed" but drawings stay alive
> and imposible to erase it!
> So a "cleaner tool" for old drawings :)

Can he post a model that shows this problem?

The videos and screenshots are great, but many times it would also be quite helpful to get a model along with them. The model gives me something that I can examine in much more detail. Some problems are also dependent on very small factors such as the position or shapes of objects, so they can sometimes be hard to recreate just by looking at a video.


> Video who show a boolean union with persistant lines!

These lines look like they are just edges where some surfaces are joined to each other. This is not necessarily a really unusual thing, imagine if you draw 3 planes and move them so they have a common edge, then use "Join" to join them together at their edges - this will create an object that has some interior edges, even though it is all one flat shape. This is likely what you have here.

But the boolean union is supposed to try and combine planes together to simplify the end result, for some reason that is not happening in some cases. If you can post a model that shows this, it would help to track it down and see if the plane-combining mechanism can be improved. A quick way to fix this is to select those faces that you don't want, do delete to remove them, then select the object and do Construct/Planar to fill in the planar hole with a new single clean plane.


> Ps Have you some plan for a "reccording script" of all actions when
> objects are modelized? For replay the creation as a pedagogic and funny way :)

There is a plan for something similar to this in the future, but not for V1 though.



> With all this thrad time of developpment will be * 3 :)

:) That's ok, this information is very important for me to get, it is of great help to me. It takes time but it helps me do more intelligent work in the future to improve the program. So it is time well spent.


> Pss For a grammatical point does the word "complaint" is convenient
> for you or "request" seems better?

:) In English "complaint" is maybe kind of negative, "request" is more polite. But don't worry Pilou, I don't take any offense, I understand you just fine which is what I really care about! :)

- Michael

here the 3dm "bugs" http://www.zbrush.fr/phpBB2//download.php?id=1055
architecture windows persistant (the rectangular block for closed the window by Boolean union) a rectangle persist!


and stairs (if you take the volumes to add, depending of their order, persistant lines are not the same!!

Ps like the volume "the wall + windows" above, does exist a reasonable limit of the numbers of windows(objects)
to booleanize ?(difference) (one by one or all in a same pass)

A translation in french of your lesson can be view here :)
http://forums.polyloop.net/showpost.php?p=108807&postcount=86

> Pss For a grammatical point does the word "complaint" is convenient
> for you or "request" seems better?

>> :) In English "complaint" is maybe kind of negative, "request" is more polite.


@ Frenchy Pilou : LOL ! This one made me smile (Frenchy and I had a discussion about the use of the term "complaint" in another forum) ;-))

> here the 3dm "bugs" http://www.zbrush.fr/phpBB2//download.php?id=1055
> architecture windows persistant (the rectangular block for closed the window by Boolean
> union) a rectangle persist!

Hi Pilou, I see now. But this is not exactly an error, it is valid to have objects that are set up like this.

Here is an example:

If I have 2 surfaces, one with a hole in it, and I have another surface that fits within the hole, I can move them together and then use "join", to get this result:

This is just two surfaces joined together - two planes can be joined together at shared edges just like any other surfaces can be joined together.

Now, if you wish to simplify this, here is what you would do - select the inner face, and do a delete, removing it and leaving a hole. Now select all the edges of the hole, and do another delete. This will remove the trimming boundary that defines the hole.

Remember that post yesterday where I was showing how trimmed surfaces work? Well, that was showing an outside trim boundary that trimmed away the outside of the surface. There can also be interior trim boundaries, which create holes inside a surface.


It would be nice if booleans always optimized planar shapes so that they would be single planes instead of creating joined pieces like this. But it will not be easy to fix this to happen in all cases for a while.

I'd recommend that when you want to remove a piece, you should use usually use delete to do it more often, not boolean union.

So for instance, to remove a window, don't create a box - instead select the side pieces of the window and delete them. Then select the open edges of the window and delete them too, removing the hole - now the window is erased and the original surface is restored in that area. You can only delete edges if they are not attached to something else, so that's why you delete the side pieces of the window in a first step.

So using this method you can repair any of those pieces that you wish to remove. Let me know if this is not clear.

- Michael

> Ps like the volume "the wall + windows" above, does exist a reasonable limit of the numbers of
> windows(objects) to booleanize ?(difference) (one by one or all in a same pass)

There isn't really any fixed limit... Sooner or later it will start to slow down but you should be able to do quite a lot of them, I think.

- Michael

Ok I understand this problem of "topology" (?) thx for the explanations!
< So for instance, to remove a window, don't create a box - instead select the side pieces of the window and delete them. Then select the open edges of the window and delete them too, removing the hole - now the window is erased and the original surface is restored in that area. You can only delete edges if they are not attached to something else, so that's why you delete the side pieces of the window in a first step.

You say "side pieces" it's well the "sides faces" not the "edges" side? (due "only delete edges if they are not attached to something")

I have delete the "faces" side prime and that works :)
But something will be very cool in this case (and useful in many other cases of course) : a "loop (or ring) selection" faces (or edges) :)
Is that possible?

@Schbeurd : You see I take heed of any informations :)

Yes, topology is it exactly!

> You say "side pieces" it's well the "sides faces" not the "edges" side?
> (due "only delete edges if they are not attached to something")

Yes that is correct, the side faces must be deleted first. This leaves open edges and then the open edges can be deleted.

But I just realized that there is a bug that if deleting the edges causes the object to become a fully closed solid (like in this case), there is a problem with the structure of the object which may interfere with some operations like booleans. The problem will be solved if you save the file and re-open it though. So until I get a chance to fix this bug you may need to save the file and re-open it after you delete holes in this manner.

Otherwise you may notice some strange problems like booleans not handling the interior parts of objects properly.


> But something will be very cool in this case (and useful in many other cases of
> course) : a "loop (or ring) selection" faces (or edges) :)
> Is that possible?

Yup, it was part of your previous list! Sometime after array and image planes are functioning.

- Michael