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TechnicSummse

Question to LDD-builders

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I see many guys building theire models with LDD. I can understand if brick-builded things are made with LDD...

... but how can you make technic models without to big problems in LDD?

 

I saw many models, including complicated geartrains made in LDD... how can you do such things? (I have even problems to fit 2 gears together in LDD)

Is there any way, how you can test geartrains/racks/any motions or technic functions in LDD? 

How do you solve (in a usable way) the problem of finding the right pinhole, fitting bushes to the right position at an axle and so on...

Do you just accept the ~10 times more time you need to build in LDD? Or are there any tricks, wich i just did not find yet?

Edited by TechnicSummse

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Nope, it's exactly as hard as you say it is. Most builders either do LDD after they are done building, or at the same time, to get a feel for the model while building in real bricks various subsystems.

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I use MLCad. There you don't have to align gears and you cannot "test" geartrains. Testing needs to be done in real life anyway. I use it to plan something inside-out, so that I can plan a function before I plan the frame that will hold it. Then when I have something testable, I build it for real. That the gears don't align in the digital build, I don't care.

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You might get some tips at the LDD forum rather than the Technic forum. But you might find that your problem is that you're using LDD, instead of an LDraw editor geared (pun intended!) towards technic use. I would suggest checking out LDCad - its interface is a little unusual, but it is quite a powerful program. And it's under active development.

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1 hour ago, TechnicSummse said:

I saw many models, including complicated geartrains made in LDD... how can you do such things? (I have even problems to fit 2 gears together in LDD)

It's all about practice and keeping a desired result in your mind. I also started from "physical" bricks, but now I'd prefer to check some assembles in LDD (that allows only legal connections :classic:) and then build it and perform some physical tests. As for gears pairing, you just should rotate one of them at 360 / (Teeth_Num * 2) degrees (half-step between two nearby teeth) and then it will fit perfectly.

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I have used LDD for instructions, but only after my model is finished. Or I update it as I build, but that gets tedious as things change often and rapidly. Yes, the gears are an absolute pain in the butt, but like @Void_S stated, rotate them. And don't use flex axles and LDD. They mix like oil and water. :sick:

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The answer is simple: just build with real Lego... :laugh:

But seriously, it's much easier to make a digital model if you have a real one - especially when it comes to flexible parts like flex-axles or PF cables.

 

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OH how I wish that Sergio wouldn't have died off so he could have kept SR3D Builder alive.

It's a powerful program geared towards technic. You don't have to align gears, and you can animate them simply by clicking one button; no coding required.

It's got all the new parts if you use a current LDraw library, however some connections won't be accepted on the new parts due to no one working on the program anymore.

What we need is another person like Sergio to continue his work.

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8 hours ago, Void_S said:

It's all about practice and keeping a desired result in your mind. I also started from "physical" bricks, but now I'd prefer to check some assembles in LDD (that allows only legal connections :classic:) and then build it and perform some physical tests. As for gears pairing, you just should rotate one of them at 360 / (Teeth_Num * 2) degrees (half-step between two nearby teeth) and then it will fit perfectly.

Well theoretically this sounds easy... but at the end, this means, i have also to rotate all the stuff allready connectéd to this gear. And if you want to connect two parts, each with own geartrains... how do you do this?

You cannot rotate simply the 2 gears wich should be connected to each other... you would need to rotate each single gear in this row... but this does not work, because it will be blocked by his follwed gear...

 

My intention to build digitally was, to be able to use parts, wich i do not own yet... and still build what i want to. And at the end... just ordering the required parts when the model is finished.

If i build physically, i need to order parts while the building progress... eating a lot of time until they arrive, and also like this i will buy a lot of stuff wich i do not need, because builds allways change until the construction is finished.

 

 

Edited by TechnicSummse

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34 minutes ago, TechnicSummse said:

My intention to build digitally was, to be able to use parts, wich i do not own yet... and still build what i want to. And at the end... just ordering the required parts when the model is finished.

If i build physically, i need to order parts while the building progress... eating a lot of time until they arrive, and also like this i will buy a lot of stuff wich i do not need, because builds allways change until the construction is finished.

This is the reason - beside optimization - why I do LDD design first and parallel start the real build. It really takes time, but doing this step-by-step is a really big help for me. After a while practicing I would say I can build in LDD like with real parts. You only need to think about how to build the parts together, what are the locked / unlocked connections, how certain parts behave.

For the gears, well, You need to rotate them 1 by 1 as You place them (rotate axle a bit, place the gear on - OK/NOK - take off gear, repeat). The big advantage of LDD comes afterwards, as connections around will be updated - to replace parts / structure without disassembling the whole build. I strongly recommend to use build groups for this, which can be hidden easily. For me, setting the gears properly is peanuts compared to the time I spend on design optimization.

HERE is an example (in the link the complete up-to date model, with groups):

800x450.jpg

This is the naked drivetrain, but to figure out a buildable, solid framework around, which serves all the required functions was the biggest challenge. At this stage live build is unavoidable, f.e.: friction can not be foreseen. Summ: I start with digital, than test the basics with on-hand parts, improve in digital (best to use modular builds for that), and check back and forth time to time. Design is done in LDD, testing with bricks.

I would say it appends on personality too, for me this method works best, I like to figure out the most effective (and wallet friendly) design, before I order extra parts.

I checked other Lego CAD softwares, but those are too "IT language" for me, I just want to drag and drop. Might be a good candidate Stud.io too, it is evolving in a good way, a bit harder to operate than LDD sometimes, but overall OK, also linked to Bricklink, and has an awesome render module integrated!

https://studio.bricklink.com/v2/build/studio.page

I hope it helps a bit.

Edited by agrof

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Copy+Paste is the most often used tool for me. I even copy-paste single parts to preserve their rotation. Building gearboxes with this method is pretty quick: you usually have to carefully align only the first few gears then just copy-paste axles to preserve their angle, insert the gear on the axle then delete the axle and insert the proper-length axle in the gear.

I usually build subassemlbies separated from the main model, so that it's easier to find the correct connection points, and rotating parts don't force the whole main assembly to recalculate rotations (if you rotate a part on an assembly, the whole assembly with its connections refresh, causing major slowdown and may even cause crashes, slight misalignments, random other parts rotating, etc)

Also, my LDD files usually contain tons of temporary assemblies and rotated parts floating around. So I can copy-paste :)
My building speed in LDD is about the same as my speed with real bricks.

I hope my post was clear and sorry for the typos, no spell-check and time in my workplace.

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@Lipko Indeed, this is a method I also use, but due to the routine, it was too obvious to mention to me... :blush: Very useful advice!

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3 hours ago, Lipko said:

Copy+Paste is the most often used tool for me. I even copy-paste single parts to preserve their rotation. Building gearboxes with this method is pretty quick: you usually have to carefully align only the first few gears then just copy-paste axles to preserve their angle, insert the gear on the axle then delete the axle and insert the proper-length axle in the gear.

I usually build subassemlbies separated from the main model, so that it's easier to find the correct connection points, and rotating parts don't force the whole main assembly to recalculate rotations (if you rotate a part on an assembly, the whole assembly with its connections refresh, causing major slowdown and may even cause crashes, slight misalignments, random other parts rotating, etc)

Also, my LDD files usually contain tons of temporary assemblies and rotated parts floating around. So I can copy-paste :)
My building speed in LDD is about the same as my speed with real bricks.

I hope my post was clear and sorry for the typos, no spell-check and time in my workplace.

 

3 hours ago, agrof said:

@Lipko Indeed, this is a method I also use, but due to the routine, it was too obvious to mention to me... :blush: Very useful advice!

Well basicly i did this also... i think i need to learn more about the hiding-function, and especially the grouping.

But when i start hiding stuff, and start grouping components... things getting confusing fast.

 

But the way you describe your building... it sounds like you need to permanently zoom in and out, to c+p thing from the edges, and then place them correctly to the model.

 

@agrof the picture looks insane... and horrible to build in LDD at the same time to me. So you just drop your gears on the digital table, bring them in position like you like it... and at the end, you start building a frame arround them?

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3 hours ago, TechnicSummse said:

 the picture looks insane... and horrible to build in LDD at the same time to me. So you just drop your gears on the digital table, bring them in position like you like it... and at the end, you start building a frame arround them?

Well, not really, it is something what evolves with overall design parallel. What You see in the picture is broken down view - I deleted / hided all the unnecessary parts, what I don't wanted to show, but the complete design was already there.

To place the axles and gears, You need beams / frames to attach them in the space. This can be very raw sketch, f.e.: beams attached by pins. Usually I have already a picture in my head, how it should look like, I build a "help-frame" - let's call it prototype, and put the gearing, axles in, afterwards I start to rethink how can be done axle holes, frame structure more effectively.

A simple example though: if You want to have a simple gear connection which for the axles will be placed like this: XOX (3 studs), just take a beam, and use it's holes for placing the axles and gears. Once You are ready, You can delete the beam.

To figure out which gear ratio what stud distances needs, Sariel made a super useful tool: http://gears.sariel.pl/

I hope it makes sense above... :classic:

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3 hours ago, agrof said:

Well, not really, it is something what evolves with overall design parallel. What You see in the picture is broken down view - I deleted / hided all the unnecessary parts, what I don't wanted to show, but the complete design was already there.

To place the axles and gears, You need beams / frames to attach them in the space. This can be very raw sketch, f.e.: beams attached by pins. Usually I have already a picture in my head, how it should look like, I build a "help-frame" - let's call it prototype, and put the gearing, axles in, afterwards I start to rethink how can be done axle holes, frame structure more effectively.

A simple example though: if You want to have a simple gear connection which for the axles will be placed like this: XOX (3 studs), just take a beam, and use it's holes for placing the axles and gears. Once You are ready, You can delete the beam.

Well basicly nothing new to me... but this is just tons of work and time :(

Do you just need to do it a few times and evrythig goes easy? :D

Quote

To figure out which gear ratio what stud distances needs, Sariel made a super useful tool: http://gears.sariel.pl/

 

Uhm... there is a much easier way for this:

-> (Gear1 + Gear2) / 16

 

(8+8)/16=1 -> two 8 teeth gears will fit to the next pinhole

(16+16)/16=2 -> two 16 teeth gears will fit 2 pinholes away from the first.

(8+16)/2= 1,5 -> a 8 teeth gear and a 16 teeth gear will fit with 1,5 pinholes away from the first one

 

and so on... its really simple :)

_____________________________________________________________________________________

@agrof i did check your ldd file... but i did not find a group showing your geartrain. But i first time realised, you can create sub-groups.

While looking through your model, i hided single groups, one after another... but i did not find a way to unhide single groups... 

...can you only unhide all stuff together? Or is there any way to unhide just single groups or parts?

Edited by TechnicSummse

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1 hour ago, Lipko said:

There is a minifig icon on the right-top that's covering its eyes. Click that.

but like this i unhide everthing...

I would like to unhide just the last hided part for example, or unhide just one group.

So lets say i am unhiding my model from outside and hiding 1 panel after another to see a special part of the frame for example... but if i accidently click a wrong part to hide... how do i undo just this last step, without the need to start hiding each part until this step again?

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Ctrl-Z, alias Undo. :classic:

Unfortunately looks like this is the only option, I also miss the click-on unhide command.

Edited by agrof

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Invert selection. Or whatever it's called. I use that for unhiding specific parts/groups.

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