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Old 8th February 2005, 07:57 PM   #1
modelracer
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Default Foxed on easy problem - duh!

Hi all, just bought ac3d and very pleased with it - created a nice exhibition stand model with it already with lights etc, vey easy and straight forward.

But!

I work in Corel Draw to make 2D objects as the drawing tools are very good - then I have imported what is in effect a straight forward shape as a dxf into ac3d.

What I am struggling to do (and to be honest I actually can't believe I cant find a way to do this) is to take the 2D oject and extrude it as a combination of paths...

In Corel I have a shape that is a combination of 3 paths (a model race track) which as you can imagine is rather like a road that joins itself back up. When i import into ac3d and extrude, the paths become seperated and i get just edges rather than a blocked "road".

I have tried the merging surfaces / changing the line type etc etc but what i actually want to do is to remove the "infield" part of the circuit to make an object which is just the track. And I cant find any way to do it - this is a super simple thing and I hang my head in shame when I admit to not being able to suss it.



The above is my abortive attempt (Version No. 3492!) , as you can see the surfaces are all seperate rather then 1 simple (track) surface.

Can anyone assist?

Cheers

Owen
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Old 9th February 2005, 01:22 AM   #2
Stiglr
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Hard to really see what you've got there, but....

Try this perhaps. Not *sure* it'll work, but maybe...

Enter vertice mode and select all the vertices on the bottom edges of the walls (thus outlining the road surfaces). Then select "Create convex hull".

You may get a lot of extra surfaces you don't want, but you should be able to select and delete large groups of them until you're left with your track surface. Or, if that's way too messy, try doing it in smaller chunks a section at a time, and each time you do a new length of road, Merge it with the road surfaces you created earlier.
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Old 9th February 2005, 06:23 AM   #3
modelracer
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Hi again.

Perhaps I am guilty of making this sound too complicated (easy for a newb perhaps)...

Below are the (I guess you could call them 2D shapes?) lines that I want to start with (the rest of the circuit will be drawn in AC3D).



The black area denotes the required resultant shape, whilst the green area shows the bits that I need to cut away to achieve the shape.

If I was in Corel/Illustartor etc I would simply select the 2 non-required bits and cut them away from the main exterior shape thus leaving holes where they used to be.

From that point I can add a texture, extrude it by a couple of mm and then start to add the scenery - the sticking point is simply getting the shape in the first place to be (in effect I think) a flat surface.

Please excuse the crap understanding of 3D terminology but coming from a 2d design background its a bit of a learngin curve .

I hope this makes more sense - essentially I just want to make a solid from this with the green bits taken away and holes left in their places - this would make my race circuit as in the upper pic.

Many many thanks

Owen
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Old 9th February 2005, 07:07 AM   #4
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Or in other words.
You want a solid racetrack. Asphalt only.

It looks like you already drew a poly outline of the track.

If we take a straight this may look like this + = vertice: - = line
----+----+----+----+----+----
----+----+----+----+----+----

Now always select 4 vertices.
----+----+----+----+----+----
----+----+----+----+----+----

Starting from one corner selecting them counter-clockwise.

Then press ctrl+shift+s to create a surface between them.

Do this for all vertices.

If you now extrude all surfaces one time by some millimeters you have a solid block-racetrack.
Be shure to select the option namend something like "close edges/sides" when extruding.

Hope that helps.
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Old 9th February 2005, 07:43 AM   #5
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cool! I will go and try that one!

The things I do in the name of modelsport....

Having said that this is the basis for a 3 dimensional fly around of for the 1:5th scale World Championships this year which I am doing as a promo for a live webcast so its worth it!
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Old 9th February 2005, 09:32 AM   #6
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all these suggestions should be fine - here are a couple more

in vertex mode, hold down shift and control then drag your mouse around sections of your track to select the vertices from which you can then Vertex->create-ordered surface. This way you can create large polygons in one go, rather than making loads of quads/triangles individually, which takes a while.

You might also try using Vertex->create-2d-mesh which will create triangles between closest vertices. Depending on the shape, you may be able to do this on your whole layout and then delete the triangles you don't need. Otherwise, doing it in sections will be better. This is the one I'd try first.

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Old 9th February 2005, 07:58 PM   #7
modelracer
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A big thanks to all for the help so far, I now got the surface together using the shift ctrl drag doohickey..

Now to establish why i cant extrude the shape - it errors with something along the lines of "no surface edges".. LOL here we go again!

Owen
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Old 9th February 2005, 09:04 PM   #8
modelracer
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Right....

Found that extruding each bit in sections does give me an extrude - but it doesnt help with combining all the sections into one lump.

When I try to combine surfaces I get (sometimes) an error like "all surfaces must be adjqacent" - which stops me in my tracks somewhat!

I think perhaps I must get all the surfaces together before attempting an extrude... is this perhaps right?

If this is the case how do I tackle this - ie: getting the results of my shift ctrl drags and shft ctrl s's all into one piece?

Quite an extrodinary length to have to go to to make a solid object !!

Owen
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Old 9th February 2005, 11:37 PM   #9
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I'd definitely try Andy's suggestion of using Vertex->create-2d-mesh and deleting the unwanted polygons. I've found the create-ordered-surface approach can give you bad triangulation if you simply drag across 4 or more vertices, and forcing the ordering by selection can be a pain if you have a lot of vertices. Vertex->create-2d-mesh seems to me a more reliable and faster method.

Good luck
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Old 10th February 2005, 03:06 AM   #10
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You won't be able to combine all of the surfaces you made into one polygon since it's a complicated shape with holes in. There's no point anyway.

Once you have created surfaces between the vertices to making your 2d track shape, switch to surface mode, select all, press extrude and drag your surfaces up. That should be fine.

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