Assembling in assembly mode doesn't fit

[Anonymous]

Currently, I am making a geodesic dome for my project, which consists of pentagon and hexagon parts. 

I have no problem with the hexagon, but I have problem with the pentagon (with the angle), and finally, I could get the value of the angle for the pentagon with not 100% precise (I got the angle by adjusting the angle value of the brown part (brown part see the picture attachments). But as long as I am finishing my design, there are many big gaps between the connector. I don't know why.

Here I attached the picture for you to understand. (I'm making the design from the top)

At 1.jpg and 2.jpg, the gap is almost nothing (you can see that there is a problem with the joint). And on the next file, the gap is getting worse.

What in my mind is, the gap at the top is so small, and why the gap at the bottom is so big?

[swalton]

Please use the Pack-n-go tool and post a .zip file of your design. It will be much easier to troubleshoot with a copy of your assembly and parts. It looks like the parts are joined by tab-and-slot joints. Are the slots oversized for manufacturing tolerances? If so, do your assembly joints have the correct offset distance?

[Anonymous]

Yes. I am using the tab-and-slot joints, and for the slot, I don't make it bigger. I just realized that all the hexagons and the pentagons are in a mess. After analyzing them all, the angle don't fit each other. For the hexagon, all the three angles are the same, but the other two angle are different and make small gap around 5.1mm. And for the pentagon is around 2mm gap with 3 angles are the same. I use all the same parts (the gray and the brown) for each hexagon and pentagon

kelly.young has attached your files as .zip for clarity.

[Anonymous]

I thought it might be a cumulative error that built up as you added new parts. I'll have to wait until this weekend to take a look at your files. I don't have a .rar decoder on my work machine. Why not use the built in .zip tool in Windows?

[Anonymous]

Here I attached the files in .zip format with the hexagon and the pentagon as my references angles.

[Anonymous]

I used the exact value of the angles from the reference pentagon and hexagon to my connector (Brown parts), and there is still a gap on both shapes.

[TheCADWhisperer]

When I open the parts my initial observation is that the geometry is poorly modeled. Is this a school project? If so, can you ask your instructor to join this discussion?

[Anonymous]

That's not a school project. I got this project from my boss at work. He wants to make a plug and play geodesic dome and he asked me. Sorry for the poorly modeled geometry because I learned inventor only around 2-3 weeks from YouTube. Is my geometry understandable?

[JDMather]

I recommend finding a new teacher. Can you post link to the YouTube video so that I can critique the presentations? I recommend that you do not proceed past this Sketch until you have mastered it. (see attached image) There should not be any repeated dimensions. The geometry should be symmetriclal about the Origin Center Point. The dimensions in the lower right do not make logical sense. Let's start by working on this one sketch and forget all else until it is fixed. Are you ready to start over and do it right?

[Anonymous]

Thanks for the critiques and suggestions. I am doing this this by myself, not from YT videos (You can't find any videos on how to make this things). What I learned from YT is only for the basic techniques on how to use Inventor. Anyway, I am not an architect, designer, or anything related with such this program. My boss asked my to do this. And what I asked is, am I doing the design incorrectly, or am I using this program in a wrong way? Because I followed the angle dimensions based on my reference.

[JDMather]

What reference are you using?

[johnsonshiue]

Hi Nicolas, I took a look at this case. It can be done much more easily in Inventor. There is a better approach. The key is to position the strut in the space correctly before you build the connector. Please take a look at attached assembly. The way I did it was I constrain the two struts first (before creating the patterns). I make sure the two are symmetric and separated by 60 deg. Then I added a Flush constraint to ensure the connector can be placed. The connector slot and the strut itself have sketch issues. They are not properly dimensioned and constrained. You need to fix it up. Also the connector slots are not created in the correct position. It can be easily fixed. Please try it out and see if you have additional questions. Many thanks!

[Anonymous]

Hi Johnson, Thanks for your reply, but I still don't really get what you mean. Why did you choose 60 deg? Is it possible to do it in simpler way, such as by only using joints, or anything? The slots look like not properly dimensioned, because the idea is to have all the same slot size. I tried to make the slot dimension on the connector in the middle of the construction line on sketch3. And the dimension of the slot in the strut follows the dimension of the slot in the connector. I still don't understand, from what you did, the dimension of the slot of the strut is 60x20mm, which is not the same for the dimension of the slot of the connector.

[Anonymous]

I got the reference for my angle dimension is from the attachment name "hex.ipt" and "pent.ipt". Then I followed the angle from that references and applied it to the connector

[johnsonshiue]

Hi Nicolas, The hexagon assembly has 6 struts around a circle. The angle between two struts has to be 60 deg (72 deg for pentagon) if you view it from top. It is better to position the struts first and then add the connectors. Your files have a lot of bad dimensions and poor assumptions. I don't think the assembly as was would yield the result you were looking for. It was simply mathematically impossible. Try to study my solution and get better understanding of the spatial relationship among these parts. I still believe my solution is valid. The only thing left for you to do is to edit the connector and make sure the slots fit the struts. Many thanks!