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jeffroyer

How would you construct this?

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I downloaded this pattern and commenced to tracing it. I'm using the polyline tool and just using straight segments that get fairly close to the shapes. Once complete (and closed), I'm using the poly smoothing tool (bezier) which gets it close enough for my purposes.

The shapes are placed over the square polyline. I'm trying to clip the surface of the square to end up with a single polyline that I can give to my laser cutter to cut these out of steel. Unfortunately, I keep getting errors where some of the polyline shapes will not clip the surface. As a test, if I try to extrude the errant shape, it gets all funky. So, something is obviously wrong.

Is there a better way to go about this?

I've done several other laser cut panels successfully with the same methodology but those shapes were geometric and didn't entail all these free form curves.

Thanks!

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The culprits are likely polylines that aren't closed or overlapping points. I'm assuming you created the detail once and mirrored/duplicated to complete the pattern. The trick is to get the building blocks to be clean geometry before mirroring/duplicating.

Can you post one of the polylines you're having trouble with?

(Note that when you create a polyline shape with cutouts you can go back in and edit the cutouts. The polyline/cutouts shape is like a group. Use Command [ to go in and edit the cutouts.)

Kevin

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Kevin,

Here is the offending shape.

I made it as one complete, non-stop polyline and it appeared to close at completion as my last click was on the starting point.

Thanks for your input!

Jeff

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Hi Jeff here's the extrude....... what I did was to use the 2D polyline tool using the flood mode and then you can extrude the shape that is created. Good luck!

Edited by Vincent C

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Jeff,

Try using Modify>Drafting Aids>Simplify Polys. If you use a maximum deviation set to 0 and run the command it will remove duplicate vertices. I tried it with your shape and there are other issues (likely intersecting geometry) because it isn't closed when you extrude it.

Another trick is to use the Extract tool on a bad extrude. I've attached a file where I extracted the top surface and turned it into its own extrude which fixes the issue. It also reduces the number of points significantly.

In general you want to keep the point count as low as possible otherwise polylines become very difficult to troubleshoot and cause a lot of overhead.

Kevin

ubbthreads.php?ubb=download&Number=14751&filename=Screen%20Shot%202016-03-24%20at%208.08.05%20AM.png

Edited by Kevin McAllister

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I wonder if it is an issue with my funky old VW 2013.

I don't get the same results you guys do.

Paint bucket. Extrude. This....

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Use the paint bucket and make sure it works. It will not work on an open shape - you can check this in the OIP (small box which says closed).

Also make sure you have a solid fill in you attributes palette. Click the paint bucket into the shape and check the bottom right corner of the UI for any errors. Also worth making sure its on the layer plane not the screen plane in the OIP

Extrude the resulting polyline and it should work fine?

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The difference between looking at this in wireframe vs opengl doesn't give me much faith in the quality of the polyline.

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Under View > Rendering > OpenGL Options, make sure to set the quality to High, it defaults to Low which can artificially make geometry look rougher than it really is.

But if you set it to High and its still rough, then it is indeed the source poly.

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Finally got it all done.

Ended up breaking the shapes into smaller shapes to contain their size. Nonetheless, this particular pattern is slowing down my poor ol' macbook pro. Time for an upgrade.

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That looks good!

If the file is bogged down, it's probably because too many vertices. If the actual geometry is not needed, an image texture could also work.

Seems like that shape could be done with way fewer vertices. In future, try making the shape with fewer points by tracing with Polyline in Cubic Spline mode or bez or even arcs. Switch to corner when needed (press the "u" key to switch modes while tracing). If the new shape deviates too much, dbl click to edit and add/move points.

Here it is with 130 spline vertices. About 10 min including edits to conform to base drawing. More edits probably needed. Could probably be done with 100 or fewer points. If I clip this from a rectangle, the new object has double the points -vwx changes them to bez points.

Some tracing tips (I've done miles) -

•Lock the base image or put it on another layer, set visibility to Show Others.

•Hold the tilda key to temp disable snaps.

•If VWX slows down while creating a poly with tons of points, start a new poly with another color. Compose all the sub polys. You may have to change the join points from corner to curve variety.

•Often, a lower res, aliased base image is easier to trace & edit than a sharp one.

-B

ubbthreads.php?ubb=download&Number=14761&filename=130%20vertices.png

Edited by Benson Shaw

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Thanks for the suggestions, Benson.

The first version of this I showed my client was through an image texture with a mask for the holes. Little did I know it would take such an effort to get real geometry for the laser cutter!!

I don't typically do a bunch of tracing - I get too impatient. I'll give it a whirl with the focus on creating fewer vertices. This file crashes now any time I try to do too much.

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I suggest asking your cutting service what kind of curves & vertices they can cut. Some allow arc & corner points only. Send a couple test files with only a few simple objects.

-B

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