MoI discussion forum > Requests &...from Pilou:)

From:

6 Nov 2006 (9 of 80)

207.9 In reply to 207.3
> About the Curve start /curve End on a rail or path is this image more clear ? > Of course curve Start, Curve End , and rail -path) can be any curve ! Hi Pilou, you can use sweep for this, choose the start and end curve, run Construct / Sweep, then select the rail. But it is more typical to have the rail running down the center of the profiles, it is somewhat easier to control things that way. Sweep with one rail will slide the shapes along the path, and it will reorient them to follow the path. When you have the rail only on one side of the shapes, the other end of the shape tends to move quite a bit when it is reoriented (kind of like it swings around a lot since it is far away from the path). With a path down the center the shapes swing in a more "balanced" way around their center points. Let me know if this needs more explanation. But you probably won't get a very good result from the curves in your image, there is just a little bit too many things going on there, there is the curve of the path and then having a circle change into a rectangle which is a major shift. To control the resulting surface better in this case you would normally need to use some more curves to define what you want better and maybe build it in a few sections. - Michael

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From:

Michael Gibson

6 Nov 2006 (10 of 80)

207.10 In reply to 207.4
> re: SaveAs IGES Hi Pilou, thanks for the additional explanation, I understand now. What is happening is when you switch the "Save as type" drop-down to IGES, the current file name is remaining as "cube.3dm". So when you go to save it is using this file name. This is actually a problem with the windows file management, it is just the way it works by default. However, it should be possible for me to customize it to make it better - in this case the file name should change to cube.igs when you change the drop-down to IGES. As a quick workaround right now, in addition to changing the file type drop-down, you can go in and edit the file name "cube.3dm" to be "cube.igs", and then it will save as IGES format. > Ps For the Tabkey for Top / Bottom yes anything you want :) > But we will be able to use the "bottom view" as the "Top view" for draw, move objects etc...? Sorry, I didn't mean the tab key on the keyboard, I mean the view tab-style control near the bottom of the screen that says "Split \| 3D \| Top \| Front \| Right". If you clicked on Top in there when it was already active, it could then switch to Bottom. It would behave the same as the top view did for drawing, etc... except for having the reverse view. - Michael

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From:

Michael Gibson

6 Nov 2006 (12 of 80)

207.12 In reply to 207.5
> > < do you consider a volume and a solid to be different things?> In the reality yes :) > You can weigh a solid, not a volume :) But you can calculate the weight of a volume for a particular material, just with one multiply. Like you can say "this volume of gold will weigh this much." But CAD is typically more concerned with the topology and forms that define a shape, not so much with what material is inside of it. Normally in CAD, a solid means an object that has a defined volume. - Michael

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From:

Frenchy Pilou (PILOU)

6 Nov 2006 (13 of 80)

207.13 In reply to 207.9
No it's not exactly that: Sweep is not suffisant :) Look after the object C, it's near the solution :) a mix of A, B ,C Another time, I believed that a Sweep with one or two rail should take juste one curve :) And not a cuve somewhere and another in the other part of the plan :D
EDITED: 6 Nov 2006 by PILOU
Attachments: task.jpg

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From:

Michael Gibson

6 Nov 2006 (14 of 80)

207.14 In reply to 207.6
> Just an automatic function "close" some hole (s) in an object when you > select the hole 's edges > Seems quasi impossible :) > Maybe by some "Sweeps" edges one by one :) As Jonah mentioned, there is a NURBS tool called "Patch" or "N-sided Patch" which is usually used as a hole filling mechanism. MoI will have this eventually but I'm not sure exactly when. But even that tool is more suited for filling an area that is rather smooth in shape, it is not good for filling in a very large area with very irregular shapes. If you have a very large hole with irregular boundaries, there is just no single definition of what the shape of the surface should be in that area. So it is not really possible to have a completely automatic system to fill any gap, any more than it is possible to have a system to automatically create the initial model's shape from nothing. Just in the same way that you create the initial shape by drawing curves and constructing surfaces, you also need to create the filling surface in the same way, you have to draw curves and define what type of shape you want to have in that area (just as you are suggesting with doing sweeps and such). To automatically fill in something complex like you're showing would require a lot of "artifical intelligence" on the part of the software... This level of AI isn't going to be ready anytime soon! :) - Michael

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From:

Michael Gibson

6 Nov 2006 (16 of 80)

207.16 In reply to 207.13
> No it's not exactly that: Sweep is not suffisant :) Look after the > object C, it's near the solution :) > A mix of A, B ,C To do it just in one sweep, you would have to use a path more like this: But it is a complex enough shape with those sharp swinging ends that are bunched together, that you would probably need to construct it in several different parts just as you have shown... As a shape gets more complex with different corners and bunched-together areas, the less likely it becomes that you will be able to create it automatically with using only one application of one single tool. It is normal that you will need to break such things up into smaller pieces. Sometimes it is also possible that you could use some additional shape curves to help define it better. With your initial curves, MoI just doesn't know that the initial shape is supposed to swing around more rapidly than the curve is turning. - Michael
Attachments: path.jpg

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From:

Frenchy Pilou (PILOU)

7 Nov 2006 (18 of 80)

207.18
I discover again than a "Sweep" can have any numbers of different profils ! So the "icone" of "Sweep" is some misleading :) A funny & terrific thing is make a sweep and after select the rails / show Points, Add Points and move the points!!! In this case (show points enable) does exist a trick for move the last point as a "tangente" ? (only warm points, and axes seems work not the "tangent" (?) ) For the moment the only I found is draw another line as "tangent" and return to the point for move it on this new line ! It's no so bad :)
EDITED: 7 Nov 2006 by PILOU
Attachments: tangent.jpg test.3dm

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From:

Michael Gibson

7 Nov 2006 (19 of 80)

207.19 In reply to 207.18
> In this case (show points enable) does exist a trick for move the last point as a "tangente" ? One easy way is to just draw a line like you mention. Another way is to select your point, then use the Transform / Move tool. Then drag a construction line along the tangent direction that you want. The Transform/Move command can sometimes be a better way to move things with precision, since the existing object remains snappable, and you can also create construction lines with it easier than you can with dragging style movement. - Michael

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From:

Frenchy Pilou (PILOU)

7 Nov 2006 (20 of 80)

207.20 In reply to 207.19
Yes!!! It was the "move tool" ! That rocks! THx! Another time no think to take a "tool" for move a point, thinking that mouse's moves (or Pen's moves:) were sufficent ! Another little thing :) That is a tangente with the last point of control "out" the curve Is it the same tangent than a point who will be near the extremity and the extremity but "on" the curve? Seems yes, but I ask the question :)
EDITED: 8 Nov 2006 by PILOU
Attachments: tangentes.jpg

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From:

Michael Gibson

7 Nov 2006 (21 of 80)

207.21 In reply to 207.20
> Is it the same tangent than a point who will be near the extremity and > the extremity but "on" the curve? > Seems yes, but I ask the question :) Yes, the way NURBS curves work is the end tangent direction of the curve is defined by the direction of the last 2 control points. But just to be clear - a point on the curve that is near the end but a small distance away from it will not have this tangent quite yet - it is only the very end of the curve that has this tangent. But I think that you have shown that in your graphic. As you move closer and closer along the curve towards the end point, the curve's tangent at that point will get closer and closer to the line between those 2 points. - Michael

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From:

Frenchy Pilou (PILOU)

7 Nov 2006 (22 of 80)

207.22 In reply to 207.21
Yes very very closer but not the same :) In the file linked... There are one big curve "curve", a little curve "straight" near the extremity and "on" it, a big curve "straight" tangente to the little curve I had no preconceived ideas of that, now I am fixed :) That maybe good to know that in particular extrem conditions :) So it's better to draw out a curve "curve" by the function "Extend" than by an tangent aligment to the control's points :) So MoI is a very cool tool for verify geometry concepts :) Ps Is it possible to have somewhere the Zoom status? (with some decimal numbers :) I have made that : a curve extend to a line, and an extension by the alignment of the control point (see divergence jpg) I made some mouse's wheel actions before see a "divergence" :) What is the "clickety clack zoom dimension" of a wheel action? I made as an approximation of 125 "single" clikety clack :) PSs Have you plan an "intersection Snap On" with a surface when you start a line ?
EDITED: 8 Nov 2006 by PILOU
Attachments: divergence.jpg tangentes.3dm tangentt.jpg

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From:

Michael Gibson

8 Nov 2006 (23 of 80)

207.23 In reply to 207.22
> So it's better to draw out a curve "curve" by the function "Extend" > than by an tangent aligment to the control's points :) I'm not sure about "better", these do slightly different things. Extend will not change the shape of the existing curve, it will add a line segment to the end of it (except if it is an arc, it will create a bigger arc in that case). This is the equivalent of drawing a line off the end of the curve that is tangent to it, and then joining the line and the curve together. Except if your starting curve is a line it will make a single new line in that case. When you move a control point, the shape of the curve will change, but if you keep the points aligned in the same direction the end tangent of the curve will be the same. > Ps Is it possible to have somewhere the Zoom status? (with some decimal numbers :) It's a little bit hard to add this in quickly because that's a piece of new UI that has to go somewhere. Eventually I think there needs to be some view properties dialog that will let you see and change a few different things about the view, including zoom factor. > I made some mouse's wheel actions before see a "divergence" :) A very small divergence is normal in many cases. Some operations such as intersections are calculated to the modeling tolerance value, which by default is 0.01, so it is not unusual that there will be gaps and things when you zoom in tighter than that. Also just mathematics in general is limited on the computer since there is only 8 bytes of data to hold each number. So the range of numbers that can be expressed is limited and this inherently creates small errors just from adding and multiplying numbers together. If you zoom in tight enough you can see these kinds of very small divergences as well. That's why many things work with a tolerance value, like for instance join will join together two curves if their ends are within the modeling tolerance of each other, they don't have to be exactly touching with 0 divergence. > What is the "clickety clack zoom dimension" of a wheel action? One clickety clack will adjust the zoom factor by 0.8 in the top/front/right view. In the 3D view it is slightly different, it doesn't change a zoom factor there instead it moves you by a percentage of the distance between the eye point and the pivot point. > PSs Have you plan an "intersection Snap On" with a surface when you start a line ? Probably eventually. But this is a somewhat difficult area since the intersection with a surface is a fairly intensive calculation, so performance is a concern there. That's why I haven't attempted to do it yet. - Michael

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From:

Frenchy Pilou (PILOU)

9 Nov 2006 (24 of 80)

207.24
Does exist some limitations or precautions with these sorts of auto Intersect surfaces? MoI manage them without restrictions? The "auto trim" don't work is that normal ? (I suppose yes :) The trim between surface and its generator's curve works fine :) PS Snap grid disable Some 2 D curves drawing with intersections a,b,c When you move a circle by one unordinary point to the intersections a,b,c there is no snaping, but if you move this same circle by its "Quadran" there is snaping on "warm point" a,b,c ! Is that normal? :) I am agree that is the same but for an ellipse? :) Aaaaaaaaaah Sorry I have fogotten another time the function "Move" ! Sorry
EDITED: 9 Nov 2006 by PILOU
Attachments: intersect.3dm intersect.jpg

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From:

tyglik

10 Nov 2006 (25 of 80)

207.25
Hi, I hope I may join you, Pilou, to attack Michael with our requests or questions..... In rhino, there is a way how to define points both in construction plane coordinates and in world coordinates for each viewport; i can type "x,y,[z]" or "wx,y,[z]". It seems that it should work identically in MoI, but it doesn't. -switch into the Front view -start point command and type 5,5 via keyboard -repeat it for w5,5 -both points lie at the same location, hmmm? Is this bug, feature or my mistake? Petr

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From:

Michael Gibson

10 Nov 2006 (26 of 80)

207.26 In reply to 207.24
> Does exist some limitations or precautions with these sorts of auto Intersect surfaces? > MoI manage them without restrictions? These are usually called "self-intersections". These types of surfaces will cause problems in several areas, especially things involving surface intersections (which includes trim, booleans, fillets). It creates a problem in the topology of an object, where one 3D point location belongs to multiple different spots on the surface - this can mess up several algorithms. So it is best to try and avoid making those types of surfaces if you want to do any more advanced operations to them later on. > When you move a circle by one unordinary point to the intersections > a,b,c there is no snaping, but if you move this same circle by its "Quadran" > there is snaping on "warm point" a,b,c ! > Is that normal? :) It's normal - when you drag an object, it will snap the base point of the drag to either the end, mid, quadrant, or (for solids) the center points just of that object. Intersections are not included because those are not points that sort of "only belong" to the individual object. It would look kind of strange for instance while you were dragging the object around and the "Int" label showed up while you were dragging it. However, having "end, mid, quadrant, or center" show up while you are dragging makes more sense I thought. Just as you realized, you can use Transform/Move to lock the base point on the intersection if you need to. - Michael

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From:

Michael Gibson

10 Nov 2006 (27 of 80)

207.27 In reply to 207.25
Hi Petr, > Is this bug, feature or my mistake? I consider it to be a feature. :) This particular thing tends to be an area of confusion in Rhino, that typing 5,5 produces a different 3D point location depending on what viewport is active. It is particularly bad in the split view where it is so easy to accidentally change the active viewport just by moving your mouse around without even clicking somewhere. In MoI this is different - simple coordinate input with no decorations (like 5,5) will always use world coordinates. I think this is really what most people would expect (unless you have become accustomed to other software that does it differently of course). That just helps to eliminate one area of confusion. The "w" syntax is supported to do the same thing just for people who are accustomed to it from Rhino. There is currently no way to type in construction-plane relative coordinates. I suppose I could add this in using a new "c" syntax, like "c5,5". What do you think about that? There is not exactly the same concept of an "active viewport" in MoI as there is in Rhino though. But internally there is a concept of the last clicked viewport, and there is also the concept of a full-screen viewport. So the way I would figure it would work is if you have a full screen viewport, it would use that viewport's construction plane, otherwise for the split view it would use the last viewport that was clicked in. - Michael

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