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View Full Version : LEGO Beams "All Straight" hole alignment issues


adengler
11-07-2011, 06:04 PM
Aloha,
We are creating Tetrix FTC robots using Solidworks and the Tetrix/LEGO Parts libraries from 3D Content Central (also downloadable from within the Solidworks app).

We are having problems mating one particular LEGO part named "All Straight". This is a very handy part because the one file is used to create LEGO beams in all standard lengths, e.g., 3 hole, 5 hole, 7 hole, etc.

Unfortunately, the hole spacing in this part appears to be slightly off compared to other LEGO pieces. The All Straight beams mate to each other (using two concentric holes) with no problem. But, mating to other LEGO parts (using two concentric holes) does not work. Of course, mating to other parts with a single concentric hole is fine. But attempting to mate a second hole on the same beam results in the following error:

"The default mate type (concentric) would over-define the assembly. Please select the mate type below"

Has anyone else had this problem?

Thanks, in advance, for your suggestions.

AdamHeard
11-07-2011, 06:21 PM
Aloha,
We are creating Tetrix FTC robots using Solidworks and the Tetrix/LEGO Parts libraries from 3D Content Central (also downloadable from within the Solidworks app).

We are having problems mating one particular LEGO part named "All Straight". This is a very handy part because the one file is used to create LEGO beams in all standard lengths, e.g., 3 hole, 5 hole, 7 hole, etc.

Unfortunately, the hole spacing in this part appears to be slightly off compared to other LEGO pieces. The All Straight beams mate to each other (using two concentric holes) with no problem. But, mating to other LEGO parts (using two concentric holes) does not work. Of course, mating to other parts with a single concentric hole is fine. But attempting to mate a second hole on the same beam results in the following error:

"The default mate type (concentric) would over-define the assembly. Please select the mate type below"

Has anyone else had this problem?

Thanks, in advance, for your suggestions.

Visually, do the parts look darn close?

Often you'll get this issue when you're mating something with a hole spacing of 2" exactly with something 1.99654". You're getting slight differences in distance that are negligible in real life due to various reasons (often unit conversion and different tolerance standards).

adengler
11-07-2011, 09:32 PM
Visually, do the parts look darn close?

Often you'll get this issue when you're mating something with a hole spacing of 2" exactly with something 1.99654". You're getting slight differences in distance that are negligible in real life due to various reasons (often unit conversion and different tolerance standards).

Right. With the first hole lined up with an adjacent piece, each hole thereafter is progressively more misaligned.

I may be able to correct the spacing in the original SW component. We'll see. :]