two edge loops and a bridge

[max_schoenherr]

hi folks, i come from the NURBS world and am quite familiar with the basics of poly modeling. however, i need a helping hand for a tutorial about bifrost i'm planning:

i created a poly cylinder, deleted the top cap, copied that object, scaled it down slightly, combined the two, selected the edge loops at the top and tried to create a bridge between them. see the screenshot. the bridge bridges the whole top of the object; in other words it creates a new cap. what i want, is a glass which i'll later fill with a liquid.

in the NURBS world i would just create a loft between two curves.

thanks!

[damaggio · Accepted solution]

In polygon world we do an extrusion to create thickness, although you can do your bridge method, it just takes a lot longer. in your method also the inner surface has to have its Normals flipped outwardly for the edges to be filled correctly and not create a whole new cap as you have described.

[brentmc · Accepted solution]

Hi Max,

I was able to use bridge but I added a step you might have been missing.

After scaling down the inner cyclinder I used Mesh Display > Normals > Reverse to make sure the inner surface normals were pointing inwards.

Then I used Mesh > Combine, selected both edge loops and used Edit Mesh > Bridge.

Note: I had to adjust the bridge offset to get the bridge to line up correctly as shown below:

--

Brent

[max_schoenherr]

excellent, thanks! i had to find the normals display menu in order to understand the topology. and i personally think that the reverse process could be automated when using the bridge command. it's so obvious that when you have to close edge loops that you want the bridge between them and no fuzz with directions.

----maximilian

[brentmc]

Hi Max,

Yes, it might be possible to do automatically but you need to make a lot of assumptions and I could see it getting things wrong - reversing the wrong shell or reversing normals in situations where you don't want them reversed.

Here is a another common bridge operation (which has a similar topology) where you don't want the normals reversed.

P.S. I haven't used NURBS modeling for a long time but in my NURBS days I can remember having to fuss with UV directions for many common modeling operations. 😉

--

Brent