Primitive substitution in the minifig arm

[Magnus Forsberg]

Copied from the review of this part: 3818s03

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At Wed Nov 6 08:40:01 2019, the following review was posted:

Reviewer: Philo
Certification: novote
Comments:
I start to wonder about the use cyli/cyls primitives within the arm parts: when they are rendered with primitive substitution, this result in gaps in the arms, very noticeable. Maybe we should inline them...
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At Wed Nov 6 16:25:02 2019, the following review was posted:

Reviewer: MagFors
Certification: novote
Comments:
Yes, I was looking at them yesterday. Don't like them.

And maybe we could also remove that kink inside the elbow? It looks like it has been "forced" to fit the primitives.
I was planing to use your knob in all minifig arm parts. Maybe it is time for a reshape, before we start making patterned arms. Gerald, any opinion?
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At Wed Nov 6 16:35:01 2019, the following review was posted:

Reviewer: Philo
Certification: novote
Comments:
"And maybe we could also remove that kink inside the elbow?" Yes!
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At Wed Nov 6 23:35:02 2019, the following review was posted:

Reviewer: GeraldLasser
Certification: novote
Comments:
I must agree with Philo, due to the primitive substitution visible gaps appear when rendering the arms., Inlining some of the prims would for sure benefit the final result

What do you mean with that: that kink inside the elbow
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At Thu Nov 7 12:40:01 2019, the following review was posted:

Reviewer: Philo
Certification: novote
Comments:
See the kink on left image: http://www.brickshelf.com/gallery/Philo/misc2/3818.png
I'd prefer to see the surfaces spared from the kink into a smoother outer elbow surface

[Magnus Forsberg]

I want to do something like this:



   


What do you want changed on the outside of the elbow?

[Philippe Hurbain]

What do you want changed on the outside of the elbow?

I did nothing. Plain regular minifig arm.

[Magnus Forsberg]

I did nothing. Plain regular minifig arm.

I can see that, but why did you place a red ring on the right image?

[Philippe Hurbain]

I can see that, but why did you place a red ring on the right image?

Sorry... Just to make clear the place where I'd like a smoother area. Looks like I failed ?

[Gerald Lasser]

I have the feeling that the lower arm is too long

   

[Philippe Hurbain]

Copied from the review of this part: 3818s03

Reviewer: Philo
Certification: novote
Comments:
Any difference with 3818p01s05.dat / 3818p01s06.dat?

At Tue Nov 5 21:55:01 2019, the following review was posted:

Reviewer: MagFors
Certification: novote
Comments:
Here's an image to explain the different arm subfiles.
http://www.brickshelf.com/gallery/MagFor...bfiles.png

s03 and s04 are divided in the elbow line, and the p01s03-p01s06 are divided in the sleeve line.

I insist on this one... do we have evidence that there are two sleeve heights???

[Magnus Forsberg]

... do we have evidence that there are two sleeve heights???

AFAIK, no.
You have to look at these subfiles as coming from two different parts.
One single-mould (3818s01-s04) and one dual-mould (3818p01s01-p01s06).

Maybe we should renumber the dual-mould part to a uXXXX-number?

Or, digging in LDD revealed that the numbers are:

16360, complete torso with dual moulded arms
16000, dual moulded right arm
16001, dual moulded left arm

These numbers are already present in the ldraw.xml file.

[Philippe Hurbain]

AFAIK, no.
You have to look at these subfiles as coming from two different parts.
One single-mould (3818s01-s04) and one dual-mould (3818p01s01-p01s06).

Maybe we should renumber the dual-mould part to a uXXXX-number?

Or, digging in LDD revealed that the numbers are:

16360, complete torso with dual moulded arms
16000, dual moulded right arm
16001, dual moulded left arm

These numbers are already present in the ldraw.xml file.

OK. So 3818s03/s04 are used only for patterned arms when only top or bottom are patterned. Makes sense. And we should rename 3818p01 as 16000p01.

[Gerald Lasser]

I have the feeling that the lower arm is too long

When measuring it, the lower arm is about 2 LDU too long.

The actual part is 25 LDU  in the library the part is 27 LDU

Furthermore the lower arm has a conical shape, see this draft, it fits the picture pretty well.

What to do now? b-version?

   


  Arm_3818_Overlay.png (Size: 459.36 KB / Downloads: 172)

[Philippe Hurbain]

When measuring it, the lower arm is about 2 LDU too long
What to do now? b-version?

If we change length we need a b-version to keep backwards compatibility.

[Travis Cobbs]

If we change length we need a b-version to keep backwards compatibility.

I'm personally in favor of a b-version that is correct. Given how long the incorrect version has been in the library, I think that very careful consideration needs to be taken to ensure that the b-version really is correct.

[Philippe Hurbain]

I think that very careful consideration needs to be taken to ensure that the b-version really is correct.

Yes!!!
We also need to update 973c01 (unofficial) and create a b-version of 979/980 shortcuts (and obsoletize current version)

[Magnus Forsberg]

When measuring it, the lower arm is about 2 LDU too long.
The actual part is 25 LDU  in the library the part is 27 LDU
Furthermore the lower arm has a conical shape, see this draft, it fits the picture pretty well.
What to do now? b-version?

What will happen to the position of the grip in the hand? Does it also move 2 ldu? Could we make the wrist longer?
Could you please add a ldraw hand in your picture.

[Magnus Forsberg]

And we should rename 3818p01 as 16000p01.

A request is in Admin mailbox.

[Magnus Forsberg]

Here is a preview of my work so far.
It's basically ready to be divided into four subfiles.


  preview.png (Size: 82.82 KB / Downloads: 151)

[Gerald Lasser]

What will happen to the position of the grip in the hand? Does it also move 2 ldu? Could we make the wrist longer?
Could you please add a ldraw hand in your picture.

Yes, the grip needs to move back as well.

The wrist is a tad too long, but that could stay IMHO

Changing the Elbow + Lower Arm, but extending the wrist would do no good. The wrist would be far too long, even if the geometry would then be fully backwards compatible.

Now one thing comes into my mind:
- Compatibility to the handles, Steering bars, hand cuffs

I tested this and even wit the shorter elbows that should work out.

   

[Travis Cobbs]

Your picture makes it look like the hand needs a b version as well.

[Magnus Forsberg]

What effect would this change have on the Minifig Generator and Willy's file Mlcad.ini ?

[Magnus Forsberg]

What effect would this change have on the Minifig Generator and Willy's file Mlcad.ini ?

Has anyone given this any more thoughts, or are you all busy tying the knot?
I want to continue with the changes in the arm.

[Gerald Lasser]

Has anyone given this any more thoughts, or are you all busy tying the knot?
I want to continue with the changes in the arm.

I have a MLCad 3.5 on my machine, but I do have a Minifig Generator where I cannot change the arm type, there's no drop down box...

THe question is how the internals of the generator work in terms of arm/hand positioning. I cannot see anything relating to the positions in the .ini

Althoguh I can select different arms (at least that'S what I see in the .ini) i cannot figure out how the compatibility with the hand works, that looks to be hard-coded IMHO

[Willy Tschager]

The "skeleton" of the generator is hardcoded into MLCad. Mike Lachmann passed the structure to Mike Heide for his:

https://ldraw.heidemann.org/index.php?page=ldminiassi

LeoCAD's generator offers you to change the arm type, but I guess the parent/child lengths cannot be changed.

w.

[Magnus Forsberg]

The "skeleton" of the generator is hardcoded into MLCad. Mike Lachmann passed the structure to Mike Heide for his:
https://ldraw.heidemann.org/index.php?page=ldminiassi
LeoCAD's generator offers you to change the arm type, but I guess the parent/child lengths cannot be changed.

So, if we change the design/length of the arm we're going to "brake" the Minifig Generator, in both LeoCAD and MLCad? Or make it useless?

I don't want to do that. I'm gonna upload arm subfiles witch only contain inlined primitives. No change of the length.

[Orion Pobursky]

So, if we change the design/length of the arm we're going to "brake" the Minifig Generator, in both LeoCAD and MLCad? Or make it useless?

I don't want to do that. I'm gonna upload arm subfiles witch only contain inlined primitives. No change of the length.

I really don’t think we should be concerned with breaking MLCad. And LeoCAD is still in active development so it can be changed before the new part goes official. We can, however, do what we did with the color issue and email Michael to make a change. I’m sure it’s trivial enough to do so.

[Gerald Lasser]

So, if we change the design/length of the arm we're going to "brake" the Minifig Generator, in both LeoCAD and MLCad? Or make it useless?

I don't want to do that. I'm gonna upload arm subfiles witch only contain inlined primitives. No change of the length.

I played around more and even when I select a different body, e.g. the skelleton one, I do not get offered the appropriate arms. So I conclude , the MLCad Minifig Generator only knows one kind of arm.

I do not know about any other generator, although in LDCad makes it easy to build your Fig from scratch, doesn't it?

Furthermore, in the MLCad Minifig Gen, you cannot select different hips, which would be required for some of the legs (and also to get different prints)

[Orion Pobursky]

I do not know about any other generator, although in LDCad makes it easy to build your Fig from scratch, doesn't it?

Yes. Part snapping does make building a fig fairly trivial. It's even easier if you use the generic shortcut, inline it, and then change the head, arms, torso, and legs via double click substitution.

[Philippe Hurbain]

I was expecting that the minifig + plate with handles assembly (as shown in this article http://www.newelementary.com/2019/11/dif...ndles.html) would reveal that 2ldu length discrepancy, but in fact it works quite well... So what?

[Magnus Forsberg]

So what?

I was right to hesitate.

Not even with the corrected legs...
Note that you had to offset the plates to fit the feet.

[Magnus Forsberg]

So what?

Well, if the position of the knob and the end of the arm is correct. then maybe the dimensions of the upper and under arm is off?
Gerald, could you please recreate your image with fixed knob and end of arm positions?

[Orion Pobursky]

Well, if the position of the knob and the end of the arm is correct. then maybe the dimensions of the upper and under arm is off?
Gerald, could you please recreate your image with fixed knob and end of arm positions?

Before we get too out into the weeds, I’d like to remind everyone that the hand plastic is very flexible so we may be seeing a small amount of flex in some of the real world examples. Also, in a real model, an error of a few degrees is probably unnoticeable.

[Gerald Lasser]

Well, if the position of the knob and the end of the arm is correct. then maybe the dimensions of the upper and under arm is off?
Gerald, could you please recreate your image with fixed knob and end of arm positions?

I will do that in the evening or tomorrow.

It is interesting how the construction worked out in Philo's model.

[Philippe Hurbain]

Here is a preview of my work so far.
It's basically ready to be divided into four subfiles.

Updated 16000/16001 on PT look good. You intend to update 3818/3819 subparts too, don't you?

[Magnus Forsberg]

Updated 16000/16001 on PT look good. You intend to update 3818/3819 subparts too, don't you?

Thank you.
Yes, I do. I ran out of time last night...