Sweep problems / Suggestions - Urgent

[robochrish]

Hi guys,

This is my first post so I am sorry if it is in the wrong area or anything.

 

I have a project at the moment with a really short deadline and I am currently running in to problems.

 

I need to create a series of "trays" that are in the shape of letters.

I am having some success with certain letters, but zero success with others.

 

I am creating these letters using a curve brought in from illustrator, and sweeping the profile that I want to use around the curve to create the outside.

I am then using presspull to create the base of the tray.

 

However, sometimes the sweep command will simply say "unable to sweep 1 selected object" with no explanation as to why.

 

Sometimes I will get the shape that I want, but it is facing the wrong way, and I cannot fix it.

 

Other times it will simply stall and then delete both the curve and the profile.

 

What am I doing wrong?

How do you suggest I go about it?

 

Sorry If I am not making sense, but here are some images to help show you what I am talking about.

 

I really appreciate any help I can get,

 

Thanks

[tzframpton]

As long as the path is a closed polyline I can't see why it would give you error. Can you upload the file so we can take a look or is this project restricted to share with others?

[nestly]

However, sometimes the sweep command will simply say "unable to sweep 1 selected object" with no explanation as to why.

 

Are you certain it doesn't also say something about a self intersecting curve?

 

Based on similar recent topics, my guess is the "curve" is either a closed spline or closed polyline that folds back on itself. If you can PRESSPULL the base, then you can EXPLODE the resulting solid into Regions, which you can EXPLODE again to get a new spline or pline to use as a path to SWEEP your profile.

[lamensterms]

My suggestion would be to make sure your SWEEP paths are clean and logical (they don't double back on themselves, no excess nodes/vertices, etc). With my experience importing from Illustrator... it is mostly best to recreate the imported lines when in AutoCAD.

 

Another suggestions is to break up the SWEEP path into smaller polylines, then SWEEP each smaller segment, and then UNION them together. Using this method would allow you to achieve more focussed trial and error - which might help you find what is wrong with the SWEEP paths.

 

Good luck.

[lamensterms]

Also, if possible... please attach a DWG containing a SWEEP path which fails, I wouldn't mind taking a look.

 

Cheers.

Edited August 15, 2013 by lamensterms

[JD Mather]

I.... a really short deadline and I am currently running in to problems.

 

I am creating these letters using a curve brought in from illustrator, ....

 

....here are some images to help show you what I am talking about.

What am I doing wrong?

 

 

 

 

Using a graphics art program for engineering design.

Graphic artists communicate with images, 3D designers communicate with 3D models - attach your dwg file here.

 

I recommend learning how to use AutoCAD to speed things up.

You should have only lines and arcs (look at your radii).

[ReMark]

I'm assuming the letters in your images above meet your criteria so what letters gave you problems and can you post an image of one such letter?

[robochrish]

Thank you for the responses guys.

I have now solved the issue for these specific letters.

I solved the problem by setting the polyline to 0 instead of 1 when using PEDIT after exploding the curve.

 

@lamensterms What would you suggest is the best way to create the curve within Autocad? I find it a little cumbersome since I am used to things like the pen tool, instead of the arc tool.

 

 

@nestly No, the curve at no point mentioned self intersecting.

@ReMark For the images above, the N was correct but the D and A were not.

@JD Mather I apologize if I seem rather new to this but I am, hence me asking for help.

I am actually a 3D artist who normally deals with software such as Maya or 3ds Max, so this is a little different for me.

 

Thank you guys

[robochrish]

Hi guys,

It appears that my problems are not solved after all.

I am getting really messy corners at certain intersections.

I have had this with some of the other letters, but they have been easier to clean as they have a clear corner, however this time the edges seem to cut straight through each other.

 

I also have the problem of filling the gaps that are left behind after having to sweep in sections.

Since I am used to actual 3D modeling this would normally not be an issue. I would simply snap the verts together to close the gap and then weld them.

I would also sometimes create a polygon between them to close the gap.

Using Autocad is extremely painful when wanted to adjust something so simple.

Does anyone have any suggestions on how I could Solve this?

 

Thank you very much guys. I really appreciate it.

 

Here is my DWG file for anyone who might be able to help:

HelpM.dwg

 

I had also considered another way of doing this by creating multiple polylines and using loft to create the surfaces. Unfortunately this crashes Autocad.

Thanks guys.

Edited August 17, 2013 by robochrish
typo

[JD Mather]

Your path geometry is a spline, yet it could be simple lines and arcs. Use the most primitive geometry possible.

If you use simple lines and arcs (fillets) joined as polyline your geometry will be smooth (and file size smaller).

 

I would probably look at changing the modeling technique as well using the solidedit>shell function.

[robochrish]

I have tried this and it is still not working.

I can now perform loft without it crashing, however it creates it as a solid object instead of it not having a top face and it does not let me delete it.

I'm not entirely sure what you mean about changing the modeling technique using solidedit>shell function. I could not find such a function.

I'm really getting stuck now

[lamensterms]

Robochrish - I understand how the tighter corners on the inside of your 'M' could cause some issues. A possible solution for this particular problem could be to initially model/create the negative space in your letters (the empty space inside and outside/around your trays) and SUBTRACT these negative space solids from another solid. For instance... You could easily create 2 straight solids to represent the inside of the vertical and diagonal segments of your M and SUBTRACT them to remove the excess around that tight corner.

 

As far as the technique use to create your path... I'd say your best bet would be to use polylines and FILLET them at the radius corners (as JD) suggested.

 

A filleted corner would create a single radius arc, which is a simpler curve than a spline. And should produce more logical results.

[lamensterms]

If you need any assistance creating the paths, I would be happy to provide an example DWG of one of your letters (if you upload the source .AI or .DWG)... But I wouldn't be able to take a look for another 9 hours.

 

Good luck.

 

------EDIT-----

 

I just noticed you have already upload a sample. Post back if you still need a hand later in the day.

[JD Mather]

I have tried this and it is still not working.

I can now perform loft without it crashing, however it creates it as a solid object instead of it not having a top face....(

 

Sounds like it is working perfectly to me?

Now all you need to do is learn how to use the solidedit commands, perhaps Imprint and Shell would be useful.

Attach your dwg file here.

 

As you use AutoCAD - be sure to read the prompts on the command line (at bottom of the AutoCAD screen).

[robochrish]

Thank you for the help everyone, but I think that I have finally figured it out now.

The method that I was attempting where I used multiple copies of my curve in different positions and then lofted them together was not working for me last time because it was creating the solid object, however I have noticed that you can change the mode to "surface" and this is now working (for now)

Hopefully this will work for the rest of them, but I suppose that only time will tell.

thanks

[JD Mather]

What is your design intent? Are you sure surface bodies are what you want? You might also try Thicken.

[lamensterms]

Thank you for the help everyone, but I think that I have finally figured it out now.

The method that I was attempting where I used multiple copies of my curve in different positions and then lofted them together was not working for me last time because it was creating the solid object, however I have noticed that you can change the mode to "surface" and this is now working (for now)

Hopefully this will work for the rest of them, but I suppose that only time will tell.

thanks

 

It might even be worth considering creating a second LOFT solid which represents the hollow of your trays, you can SUBTRACT this solid from your first lofted solid. If it's ACIS SOLIDs you desire, this could be one way to achieve them (JD's thicken suggestion will also produce ACIS SOLIDs).

 

One pointer when using LOFT... I find that I get the most predictable results when all the source polylines have the same ammount of segments. For example, if you were LOFTing a tapered rectangle with radius corners... you would need 2 rectangle shapes/polylines, with filleted corners (each shape being a different size, but both having 8 segments - 4 edges and 4 radii at the corners). Of course this approach is not always possible, depending on what shape you wish to produce.

 

I hope that makes enough sense to be useful.

[JD Mather]

... (JD's thicken suggestion will also produce ACIS SOLIDs).....

 

Nope. Autodesk dropped ACIS many years ago.

Autodesk now uses Autodesk Shape Manager (ASM) solids.

 

You can still save as ACIS (*.sat) with the acisout command, but that saves an old ACIS v7 file. ACIS is now up to something like ACIS v18 or beyond.

 

ACIS is owned by Spatial which is owned by Dassault which is the parent company of Autodesk competitors SolidWorks and Catia.

 

http://en.wikipedia.org/wiki/ShapeManager

http://www10.mcadcafe.com/nbc/articles/view_article.php?articleid=206832&section=Magazine

[lamensterms]

Autodesk now uses Autodesk Shape Manager (ASM) solids.

 

Ahhh, so AutoCAD's SOLIDs are now ASM SOLIDs rather than ACIS?

 

I wasn't aware of that, thank you for clearing that up JD.

[robochrish]

Thanks for all of the help guys.

The intent of the models is that they will be sent to a mould maker to create plastic versions of them.

It all seems to be going fine now, thanks.