Hi David, I was able to repeat your boolean merge problem over here.

It appears to be a bug in the display mesher, your actual object seems to be fine but just the display mesh generated for it is not correct.

If you export to a mesh format, the export mesher will do a more careful job and make a good result.

The display mesher is oriented towards doing things quickly and one of its shortcuts seems to have had a bad effect in this particular case.

I'll put it on my list of things to look at in the future.

For now if you can get a proper export, just ignore that particular error.


Actually you may even find that if you save the messed up model and re-load it again the error may be gone.


Pilou, you may not have seen it because the display error will not show if you have some different settings for the display mesh angle.

- Michael

Thx for the explanation of this mysterious thing :)

Hi MIchael ...

SOrry if this turns out to be a double post ... I sent a model a little while ago but it seems not to have arrived.

Here it is again ... it seems to be a single solid but won't upload to shapeways.

cheers,

eric

Hi eric, could you also let me know what parameters you are using for saving the STL file so I can test with the same parameters over here?

But there seems to be something wrong in this area of the model here:









Looks like possibly a bad trim in that area, maybe a self-intersection or something like that, I'll see if I can repair it for you.

Also, the model does not seem to be totally symmetrical - a couple of those pieces in that problem area are shaped differntly than their adjacent neighbors, is that intentional or should those little pieces all be the same around?

- Michael

Hi eric, I've attached a repaired model here, please give this one a try and see if it will work now.

I'm not sure how that area got messed up, but there was an area that had some edges missing, there was a big gap between some edges in a trimming loop in that spot.

Anyway, I repaired it by extracting that area using Edit/Separate, breaking it into some individual surfaces and doing some untrimming (that's where you select all edges and delete them to recover the underlying surface).

That let me reconstruct one of those side pieces, which I then moved slightly (the originals were slightly off center), then arrayed it and unioned it and joined the repaired piece back into the main model.


I don't really know how that messed up area got created, possibly some kind of intersection bug but unfortunately it is difficult to track down what happened just by looking at the completed model.

Let me know if you still have any problems with the repaired version.

- Michael

I was just looking at the model too. I just wanted to point out for anybody that I used "ExplodeMove" to reveal the problem. Although Michael is much better at understanding what he found and fixed it, I found a pile of fragments in this area that the explodemove command revealed very quickly. I would have probably rebuilt the whole intersection. Perhaps all the fragments were just a byproduct of the one bad trimmed surface Michael repaired. ANyway, thought it may be useful.

Hi Michael ...

Yes, the pieces are not symmetrical ... they are the opposite sides on an unsymmetrical portion of a 2 dimensional symbol. A Tibetan letter (text) so to speak.

I'll see if this one (you fixed) will upload and let you know ... and thanks.

I do wonder how the error happened ... all duplicate parts should be the same ... they were made from one part and then arrayed.

eric

Hi Michael ...

The model you repaired uploaded to shapeways just perfectly.

I originally increased the polygons to about 75% on the export slider (the one that failed) ... I did the same thing with the repaired one.

thanks for all your help.

I have ordered a small 3d print of this and a few other things ... I'm very curious about how they'll turn out.

cheers,
eric

Thank you Pilou and Michael ;-)

Hi eric, it would be cool to see a picture of the actual model when you receive it.

It's always so cool to see these models appear in physical form, it's kind of like magic.

- Michael

Hi Michael ...

I will do that ... I have sent in 3 objects so far, so I will get pics of all three.

cheers,
eric

My little bit of fun using the concepts of this thread
Brian

Ah! Creative minds run wild!

cheers,
eric