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badderjet

Joining cylinder and sphere - advice please

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I have spent many many hours practicing on a variety of tutorials before embarking on creating my first aircraft and I am having difficulty with creating a seamless join.I have seen postings suggesting that the best way to deal with a cylinder and sphere join is to delete the join and create new polygons. This I have done, but the resulting polygons have a flat surface as shown in the attachment.Ultimately I want to have an aircraft that does not have a huge polygon count and it seems that a tessellation might assist, but as soon as I tried that the polygon count increased dramatically, and that was only on one of 16 surfaces (it also didn't seem to help overcome my problem of a flat surface).I am hoping that some of you can guide me towards a more satisfactory outcome than the one I have created.Many thanksMike

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Hey Mike.Here's how I do it:First, as a note, by looking at your screen it seems the cap ended up a bit smaller than the cylinder. Make sure they both have the same radius.Make your cylinder, make a cap of same radius, then move the cap so that it is basically just touching the end of the cylinder you want to attach it to. Then all you have to do is weld the vertices (if you don't know how to do this, let me know, I'll ellaborate). Just make sure you have the same number of sides on the cap and on the cylinder, so you end up with the same number of vertices. It is possible to have a different number of sides, but then it will be harder to have a very smooth transition, although still achievable.

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Hi FabioMany thanks indeed for the helpful instruction.I had not used welding previously and finally seemed to be able to make it work.Actually ended up using the XYZ spinners in bottom menu to zero the two parts together, then selected the verticies on the join and a minimal weld tolerance and it worked!Then selected attach and also did attach with elements, edges, faces and polygons.The colour seems even shading between the two parts so I assume it is all correct. I cannot find any misfit under high zoom view, so I assume the little mark where the weld is will not show up when I eventually complete and export the aircraft. Can you confirm that for me please(over-anxious constructor here).Thanks again.CheersMike

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Hey Mike.It sure sounds like you've done the right thing. I am just not sure what that black line in the contact position of the two parts is, I don't think it should be there. But I use 3ds max, so there might be display differences.Also, I don't think it is necessary to join the two parts in all levels like you mentioned. I believe a simple select of the parts (with no sublevel like edges or vertices activated) and then an attach works, but I am not sure.Glad to see you are making progress though!

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Look in the left lower user view, maybe it's just the vertex inside. Try deleting those inner polygons which are ending in that one vertex.

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Even better, try deleting that one vertice in the middle, and all those polygons should disappear. But be ready to undo, sometimes getting rid of some polys in some places screws parts in other places (not often though).

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To Badderjet and FabioA thousand thanks indeed. Have just tried removing the central vertice (there were two, one from the cylinder and one from the sphere) and when I removed the second one the problem disappeared.Wonderful!CheersMike

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>I have spent many many hours practicing on a variety of>tutorials before embarking on creating my first aircraft and I>am having difficulty with creating a seamless join.I've already read the other replies, but just for another point of view... :)I wouldn't have bothered to create a separate 'cap' to join with the cylinder. I would have simply extended the cylinder outwards more, created the necessary vertexes with the 'slice' tool, and then used the Uniform Scale tool to draw the vertices together until the shape was how I liked it. The end vertices would have been scaled downwards until a 'weld' would have turned them into one vertex.This is a simple technique and requires no hassle of 'joining.' Voila! A perfectly rounded and seamless 'cap' for the cylinder... :)BillAVSIM OmbudsmanFounder and Director,Creative Recycling of Aircraft Partshttp://mtco.com/~rsam/fartslogo.jpg

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Very true, or create a sphere, delete the bottom half below the center line, fill the gap (hole), and extrude the flat face to desired length. Apply smoothing group as necessary.CheersBob C.

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Don't you love having all this flexibility? I do :D.

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Thanks to one and all for the useful responses.I have learnt a great deal, have taken a copy of all the ideas and will enjoy practising these varied alternatives.Much appreciated.CheersMike

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Mike, may I also suggest something else. If that is a fuse you are making. Most designers don't bother making a cylinder and a hemisphere for the nose. Just simply make a cylinder and using the scaling tool scale all the vertices in both side and top view to create the nose shape. Hemisperes take up too much polies, which may not be benificiary to your model. Just a suggestion.Take care,Udo www.YeoDesigns.com

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>Great Mike! Glad we were of help!Fabio spoke for us. He said it. :-)Etienne :-wave

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