creating oblique watershed base

[bfertig]

Hi Tracey
I'm making a oblique watershed base map for Barnegat Bay, NJ, USA. I have the outline of both the estuary and the watershed in vector line format (or can do otherwise) that I've exported from GIS into AI.
 
I tried using the Effects-->3D-->Extrude and Bevel tool, but it took several hours and honestly looks like crap (see attached). I think it might have something to do with how complicated the outline is -- its a LOT of little lines, though I tried making it simpler.

Have you posted instructions for making oblique watersheds elsewhere on the forum that I've missed? If not, am wondering if you wouldn't mind sharing/posting.

Once I get this Barnegat base map looking alright, I'd be happy to send it over and share it for the IAN symbol library, if you like.

Cheers,
Ben

[TraceyS]

Hey Ben,

This isn't actually my specialty, so I might get Jano to chime in here too as she's had a lot of experience doing this for the coastal bays and lots of other maps.

I had a look at your attachment and I think you're on the right track. What I'd suggest is that you try to simplify the outline first as GIS files typically have thousands of extraneous points.

Select the outline, go to Object>Path>Simplify, and then you can play with curve precision and angle threshold to get something that works. Make sure you click the Preview box to see how many points are being eliminated, and the new shape - you can even select 100% curve precision and it may still eliminate additional points.

When you go to make it 3D, (Effect>3D>Extrude & Bevel), make the extrude depth 0 pt, and leave Bevel at 'None'. That effect is probably what is taking so long and making it so messy. I'll ask Jano what she does here... but for me to include it in the symbol library, I need you to expand the 3D version (Object>Expand Appearance), and then I'd add the "extrude depth" manually. Let me know if you want tips on how to do that too.

So let me know how it goes!

Cheers,
Tracey

[JaneT]

hey guys,

I actually don't use the 3D function for the extruded/beveled effect. I get the outline looking how I want using the 3D effect, then expand the object (making sure there are no gradients). Then, I copy the object and paste it behind. I then move the pasted object down however far you want the beveled/extruded distance to be.

Then it gets a little complicated. I do various cuttings and joinings until I have what looks like a ribbon that matches the outline of the object and looks like an extruded object. Then you can adjust the gradient of that ribbon so it looks like the shape goes back and forth with the object's outlines.

I hope this helps!