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pnevai
04-18-2016, 08:34 AM
To quote a line from My Cousin Vinnie, "What a F'N Nightmare!"

I have a compound curve object, I have created hatch opening in that object that precisely follow the curves and contours of the curves. The hatch must be seamless with the rest of the mesh when closed and open in the correct orientation with the imaginary hinge line. The hinge line is curved but only on a single axis so that is not a problem. But the hinge line has bank and rotation values that are not in 90 degrees to the object. Also the hatch it self is not located on any flat area of the mesh. Obviously this hatch is created when modeming the object and then cut and pasted into it's own layer, this way it is located and oriented correctly when the object is opened in layout. But that's when things get out of control. I position the pivot point on the hinge line and use pivot rotate so the hatch should rotate at the proper point and orientation. But when I actually perform the rotation it is as if I never changed the pivot rotation al all. I notice when I select rotate pivot the handles are where I set them. But when I click on rotate the handles flip back to the standard default position. I finally got this squared away with using a null, but as I said before "What a F'N Nightmare" It took hours and hours getting all of the curves of the hatch to align properly so it blends seamlessly back into its parent object and open and close properly. Literally having to move and rotate the object .05 degrees and inches or less at a time. In this instance I had only one of these to do. I cringe if it ever came to having a situation where this has to be done dozens of times. If anyone wishes to try this create a sphere, subdivide and then rotate the sphere and rotate it say 30 degrees on pitch and bank. Now cut out any single polygon and past it into a new layer. Open the object in layout and then try to get the cut polygon to open and close along one of the sides (hinge line) so it seamlessly blends with the background sphere. Something so simple should not take hours to complete. The above sphere example is simplistic because there is only one polygon side to deal with. In my case the hatch is not a single quad with straight sides. It is a complexly shaped compound curved object. Am I missing something? Has this been fixed? In modeler you can select any two points and define them as imaginary hinge about which you can rotate an object but nothing like in in layout.

RebelHill
04-18-2016, 08:45 AM
select 2 point in modeler, copy/paste em, create skelegon... you now have a bone you can get in layout thats oriented exactly to the line. Pivot record it to align its axes.

pnevai
04-18-2016, 09:03 AM
I tried to create a skelegon doing this. But how do I create a skelegon by selecting two points using point mode? I select two vertex points and highlight them then click create skelegon and click activate. Nothing happens. I can draw the skelegon in but it ends up being nowhere near the hatch object and certainly not at the parallel angle. As I said this object is not at zero coordinates nor at zero rotation.

pnevai
04-18-2016, 09:13 AM
Hatch object. Trying to create a skelegon using point mode.
133474

clintonman
04-18-2016, 09:23 AM
Maybe he meant that you draw the skelegon anywhere then weld the ends to the 2 points that where copied.

ernpchan
04-18-2016, 09:56 AM
I tried to create a skelegon doing this. But how do I create a skelegon by selecting two points using point mode? I select two vertex points and highlight them then click create skelegon and click activate. Nothing happens. I can draw the skelegon in but it ends up being nowhere near the hatch object and certainly not at the parallel angle. As I said this object is not at zero coordinates nor at zero rotation.

Turn your 2 point selection to a line. Then convert the line to a skelegon. Then delete the original line.

RebelHill
04-18-2016, 10:14 AM
yeah as ernest say, its convert, not create... thought the welding thing'd work too.

pnevai
04-18-2016, 10:50 AM
No Go, Lightwave still puts the pivot point of the skelgeon at 0,0,0 and I have to manually adjust the pivot point like I did with the Null or the object its 'self. I need he pivot point to align with the long axis of the skelegon / bone. Back to the same issue I had. I can do this with a null as well but it takes forever. I can record pivot rotation and location but those will be from 0,0,0 and not at the centerline of the bone. This has the same issue as trying to orient the pivot point of the layer object it's self. In this case using a bone as a proxy. It would be so much simpler to have the pivot point snap to a vertices and inherit its angular information. I guess there is no quicker and less tedious way of doing this in LW. Does not matter if I use local vs world coordinates, in Layout rotation seems to want to use 0,0,0 world for everything. Which makes modeling anything where the parts have to fit precisely when brought into layout a nightmare. Imagine having to model these types of things then copy them into a new layer then align everything to zero. Then in layout try to fit the part back in seamlessly at the rotation angles in this example.133475

jeric_synergy
04-18-2016, 11:20 AM
Turn your 2 point selection to a line. Then convert the line to a skelegon. Then delete the original line.
I was surprised, like the OP: disremembered the skelegon process.

This seems ripe for scripting.

jeric_synergy
04-18-2016, 11:24 AM
Just as an aside: a literal, physical hinge always has to be straight, doesn't it? :stumped:

Or, coaxial pins, right? For instance, airliner doors fit a curved fuselage, but somewhere back there there're rotating pins on the same axis.

RebelHill
04-18-2016, 11:42 AM
No Go, Lightwave still puts the pivot point of the skelgeon at 0,0,0 and I have to manually adjust the pivot point like I did with the Null or the object its 'self. I need he pivot point to align with the long axis of the skelegon / bone.

Record pivot rotation.

pnevai
04-18-2016, 12:31 PM
133476
OK with some experimenting. I created the skelegon in modeler by connecting it's ends (welded the points) to two appropriate points on the object that I wished to be the imaginary hinge. In poly mode I selected the skelegon and in the utilities menu I found a utility called assign pivot or something like that. I clicked on that, saved the object and sent it to Layout. I converted the skelegon to a LW bone and clicked on rotate. Low and behold the pivot is in the proper place and also in the correct angular orientation. as shown in the attached image. The hatch now rotates along the long axis by adjusting the Bank handle. So I parented the layer to the layer containing the body object and now everything moves together nicely. As I said I had already accomplished this in another file using null objects but this is far faster. I will still need some nulls to animate this whole thing as all you know it has to spin and rotate in any direction and angle. But getting all of the bits and pieces to fit and move the right was has become a whole lot easier. Thanks guys for pointing me in the right direction.

pnevai
04-18-2016, 12:52 PM
"Just as an aside: a literal, physical hinge always has to be straight, doesn't it?

Or, coaxial pins, right? For instance, airliner doors fit a curved fuselage, but somewhere back there there're rotating pins on the same axis. "

You are correct, in the real world this sort of thing has sound mechanical solutions and or the designers do not put themselves into a situation where they need complex hinging mechanics to solve. But this damned object is a creation of Hollywood where often times things are not based on reality. What works on in a movie environment is often completely impractical in the real world. For example this hatch when actually created with the apparent hinge points and mechanism would have serious binding issues as there is no real straight line between point a and point b There would be a horrendous gap at either end or collision at the center. (Have you ever seen a real bent hinge that worked in real life?) In our 3D world this obvious flaw can be hidden using the correct camera angle. So the viewer never sees one object passing through another during animation, or the unsightly gap. So long as the part looks right when in either the open or closed position and moves correctly all is good any weirdness during the animation can be hidden without much issue. The hinge line in this instance would be a Straight line at the ends of a curved object (Think Bow String on a Bow) is this a practical, sound solution of the real world? Not really, but this is not the real world.

jeric_synergy
04-18-2016, 12:59 PM
Indeed, hide the crazy stuff: but, engineers do incredible things with offset arms and whatnot. Heck, a car hood (old-style, like a '57 station wagon) hinge is a marvel of balance. Airliner doors too, as mentioned.

MarcusM
04-18-2016, 01:42 PM
I felt this pain a litle last time when i modeled open doors in ship and then tried open them correct to modeled hinges.