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Keet
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Sketch-A-Graph type of hinge deformation

I'm sure I'm going to give Emmanuel a head ache with this one...

Imagine a ladder where each step is connected to the sides with hinges. This means that if you lift one side all steps go along and if you lift far enough the steps will be almost vertical and the side almost touching.

This is a real world, existing product:



And of course I'm trying to create an object like this. I tried just about everything I could think of but I can't get it to work, not even close. I studied the MultipleAxisTest example and reviewed the flexiblehose. I tried combining the correct parts to the double hinges. Using the "_and_" between doubles. In most cases Sweethome3d can't even import the object and when it does it sometimes shows an incomplete "modify openings" dialog. I can't even get it to work with a single step between the two sides.

Am I doing something wrong or is this just not possible?

Keet
[Aug 9, 2022, 3:29:40 PM] Show Printable Version of Post    View Member Profile    Send Private Message [Link] Report threatening or abusive post: please login first  Go to top 
Daniels118
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Re: Sketch-A-Graph type of hinge deformation

I don't think the new feature is suitable for this purpose for two reasons:
1) As far as I understand it allows to have a hierarchy of nodes, i.e. a tree, where each node can have one or more children, but only a single parent. In your case, if you start from the fixed side, each step is a child (and it's ok), but then the moving side should have each step as a parent, which isn't feasible.
2) the problem is much more complex because it involves solving mechanical constraints, which requires ad hoc code.
[Aug 9, 2022, 5:35:00 PM] Show Printable Version of Post    View Member Profile    Send Private Message [Link] Report threatening or abusive post: please login first  Go to top 
Keet
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Re: Sketch-A-Graph type of hinge deformation

Thank you Daniele, I was already afraid that it wouldn't be possible. The 'chained' part hadn't percolated in my brain yet.

I started with a pin as a hinge on the left (wall) side of a step fixed in the left wall side upright. Of course I could swivel the step up and down as expected. I then added a second hinge on the same step on the right side. The step including the second hinge moved as expected. From there I ran into problems:

I added the right side upright placing it so the right pin-hinge was fixed in that side. I could still move the step but of course the right upright didn't stay vertical as I wanted but swiveled with the step. So I added the opening_on_hinge_2_ string for the second pin to the already present opening_on_hinge_1_ on the right upright. I hoped that adding the second opening_on would follow the movement for the second pin AND the first pin, but alas, I couldn't even import the object with those strings.

I suspect that the "sweethome3d_opening_on_hinge_1_and_sweethome3d_opening_on_hinge_2_1" as set on the right upright was the culprit, although I hoped it would work from what I read here: http://www.sweethome3d.com/support/forum/viewthread_thread,11818

As you said, it's a chain and what I want is (currently) not possible. For now I more or less 'solved' it by pulling the right side out as a drawer but that of course requires a wall behind it where it can go into without sticking out at the other side. Fortunately in my current project I can do that because it alignes with a wall on the inside.

I think the design for the escape ladder is incredible. You don't see large ugly stairs and it can't be used by burglars because it's locked closed. It takes up so little space. Only at the top can it be opened by pulling a pin that locks the two sides together. A really smart design. And I wanted to create it as very little part of my current huge project.

The mechanical constraints shoudn't be a problem in itself. There are other programs that do similar things so technically it's possible. But it might run into the limitations with the current code. It would be nice though if you can pose a mannequin arm by moving the hand smile
[Aug 9, 2022, 7:54:16 PM] Show Printable Version of Post    View Member Profile    Send Private Message [Link] Report threatening or abusive post: please login first  Go to top 
Puybaret
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Re: Sketch-A-Graph type of hinge deformation

I agree this escape lader is nicely designed.

About simulating its deformation with Sweet Home 3D, Daniels118 was right to mention that the shapes bound to eachother must form a tree.

I suspect that the "sweethome3d_opening_on_hinge_1_and_sweethome3d_opening_on_hinge_2_1" as set on the right upright was the culprit
This kind of syntax is not correct: at the left of _and_ separator, there must be a text starting by sweethome3d_rail_, sweethome3d_hinge_ and sweethome3d_ball_, i.e. the name of the shape used as an axis or a ball.
At the right of _and_ separator, there must be a text starting by sweethome3d_opening_on_rail_, sweethome3d_opening_on_hinge_ or sweethome3d_arm_on_ball_ which will reference the rail, hinge or ball to which the shape you're naming is attached to.
You should probably use a name like sweethome3d_opening_hinge_3_and_sweethome3d_opening_on_hinge_2_1 and unfortunately, don't hope that some two way constraints can be applied between shapes.
----------------------------------------
Emmanuel Puybaret, Sweet Home 3D developer
[Aug 10, 2022, 10:35:03 AM] Show Printable Version of Post    View Member Profile    Send Private Message [Link] Report threatening or abusive post: please login first  Go to top 
Daniels118
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Re: Sketch-A-Graph type of hinge deformation

@Keet
I more or less 'solved' it by pulling the right side out as a drawer but that of course requires a wall behind it where it can go into without sticking out at the other side. Fortunately in my current project I can do that because it alignes with a wall on the inside.

A general workaround could be to use 2 different materials, one for the sides and one for the steps, so that you can hide the steps from the material editor window when the ladder is closed.
There are other programs that do similar things so technically it's possible. But it might run into the limitations with the current code.

Yes, I did mean that SH3D doesn't have such feature [yet].
It would be nice though if you can pose a mannequin arm by moving the hand

This is called inverse kinematics and it's quite easy to implement, but as long as SH3D joints doesn't support limits, it could lead to strange poses (i.e. elbow bent in the wrong direction, etc.), and you have to recover manually.
[Aug 10, 2022, 11:32:38 AM] Show Printable Version of Post    View Member Profile    Send Private Message [Link] Report threatening or abusive post: please login first  Go to top 
Keet
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Re: Sketch-A-Graph type of hinge deformation

That's easy since I usually create pretty detailed furniture with most parts having their own material, even if some parts commonly use the same textures or colors.
In my current project that's not necessary because the ladder slides conveniently in a wall on the inside but it's a good solution where that's not the case. It's not unthinkable that I move the ladder 20 times in the next few weeks before I'm satisfied with the result laughing
And then the process repeats when I move to the next building in my overall project.
[Aug 10, 2022, 5:52:11 PM] Show Printable Version of Post    View Member Profile    Send Private Message [Link] Report threatening or abusive post: please login first  Go to top 
Keet
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Re: Sketch-A-Graph type of hinge deformation

I have another deformation problem not unsimilar to the sketch-a-graph type of deformation.

I have a double wall created of frames and glass. The lower part of the wall is a separate part that can slide upwards in front of the upper part. Basic deformation and that works flawlessly.

I have also created double glass doors that open with separate hinges for the left and right door. Again basic deformation and also works flawlessly.

But now I want to fit the doors into the lower half of the sliding wall so that the doors go up with the lower wall when it slides up. I have added all required sweethome3d_* strings and for the opening doors this means two strings: opening on a hinge and 'opening' when sliding on the rail for the sliding wall. I concatenated the two string for 'opening_on' with '_and_' but as I halfway expected only the first one works and only the parts of the door that don't open on a hinge go up with the wall (like the outer frame). Of course the hinges themselves also have two strings, the hinge and the opening on the sliding rail and those parts do move with the rail because these are chained in the expected way. Since the two deformations for the doors aren't expected to be interacting I had a little bit of hope that both deformations would work separate from each other.

For this specific situation I have solved it by making the doors non-opening so they can go up with the lower wall as an integrated part of the complete wall object. (It's a pretty silly sight to have the doors open when the wall slides up so no problem.) I have the doors as a separate piece of furniture for other places where the opening is left as it was.

I wanted to solve this because I am going to use that specific wall object in 20+ places and thus wanted it as a single object.

In short: another situation where some extra functionality with deformations would be very welcome laughing
[Nov 8, 2022, 7:16:40 PM] Show Printable Version of Post    View Member Profile    Send Private Message [Link] Report threatening or abusive post: please login first  Go to top 
Daniels118
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Re: Sketch-A-Graph type of hinge deformation

Can you share the non-working furniture?
[Nov 9, 2022, 6:19:01 AM] Show Printable Version of Post    View Member Profile    Send Private Message [Link] Report threatening or abusive post: please login first  Go to top 
Keet
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Re: Sketch-A-Graph type of hinge deformation

Can you share the non-working furniture?
For some reason the images don't show but can be downloaded.
The objects are still in the prototype stage so are there imperfections (like no glass in the upper part yet).

Image of the 'broken' wall where only part of the doors slide up and the rails and hinges are marked: https://www.mediafire.com/file/w1xfjdcenee7ddv/SlidingCorrect.png/file

Image of the fixed wall where all three lower parts slide up: https://www.mediafire.com/view/jdpggxgzuqf6k5s/SlidingBroken.png/file

The corrected wall (obj/mtl): https://www.mediafire.com/file/wl3k5k8s8bocc3...28No_hinges%2529.zip/file

The 'broken' wall (obj/mtl): https://www.mediafire.com/file/ynsvfpp8gqv2qtq/WallSlidingBroken.zip/file

The objects parts for the complete wall (obj/mtl): https://www.mediafire.com/file/j9c13k9y1tclss1/GlassWallObjects.zip/file

The doors (obj/mtl, read the txt inside the zip): https://www.mediafire.com/file/07plitilhg0nywh/EmergencyDoors.zip/file
(The doors with hinges 1 and 2 represent a finished piece of furniture and be imported separately as Door or Window)
[Nov 9, 2022, 8:15:20 AM] Show Printable Version of Post    View Member Profile    Send Private Message [Link] Report threatening or abusive post: please login first  Go to top 
Keet
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Re: Sketch-A-Graph type of hinge deformation

(By accident I switched the images for fixed and broken)
[Nov 9, 2022, 8:19:06 AM] Show Printable Version of Post    View Member Profile    Send Private Message [Link] Report threatening or abusive post: please login first  Go to top 
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