On a face I have drawn circle and then a tube from it. The end needs to be formed like on the image. First I tried TGI-3D’s Cross Sections tool, but the faces disappeared. This already happened to me but I don’t see why. I revered changes on the cylinder and tried different method. I have selected the ending circle (bottom on the image), selected Move tool, pressed ctrl and copied the circle. Using shift on blue axis, I have move the circle up and I have change the diameter. This way I copied the second circle and did similar. This way I have formed the bottom of the tube. But some faces disappeared (and as I remember, there were already this reverted faces when I have placed the copied circles on the cylinder’s surface. So, using soft pen I have added the faces which were missing. And now I need to understand what I did wrong that this reverted faces has been created and how to correct them.
I add two images.