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Generic Transform: Skew: works on 3D objects?
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October 01, 2012, 01:01:05 AM
I can skew a 2D object, but not a 3D object.  When I try to skew a simple box, I select two bottom corners as both source and destination.  Then when I click on the third point, the Preview shows me the result I want, but after I click Finish the command has only rotated and scaled the box not Skewed it as was shown in the preview.

Am I doing something wrong, or is the Generic Transform only good for Skewing 2D objects?  Thanks.

I viewed Rob Berry's Skew Video -- which goes all the way back to new features in v9 -- where Skewing was a new.  I clicked all the right boxes as Rob did, but this only seems to work on 2D -- 2D was shown in the Example there.  However, Generic Transform will select a 3D object, and you think it's really going to work for Skew.

(I need a 3D skewing feature!)  Please advise.
« Last Edit: October 01, 2012, 01:14:07 AM by T. Karlmann »

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* October 01, 2012, 01:50:11 AM
#1
Are you using 32 or 64-bit, Thomas?  In 32 bit, for me, GT works exactly like modify|assemble|by 3 points - but with any selection, or group of selected objects, instead of being restricted to one object or group, and it shows rubber-banding while it's agile.  For me, it doesn't incorporate scaling, only rotation and translation, as part of a transformation.  Two stationary points give an axis of rotation, the third match gives angular displacement only.

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October 01, 2012, 05:53:59 PM
#2
I was using 64-bit.  However, from your answer I was not sure, did you get a skewed 3D object?

There is a button in the tool to determine if you get scaling, I think.
« Last Edit: October 01, 2012, 05:55:38 PM by T. Karlmann »

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October 01, 2012, 06:48:03 PM
#3
Still having the same issue:  Skew not working in 3D.  I just tried the same operation on a 32-bit machine.  Results attached.

Does Generic Transform work on 3D objects?

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* October 01, 2012, 07:51:34 PM
#4
Okay, I've got you now.  No, GT doesn't distort 3D objects like that; it doesn't alter the relationship between an object's features.  TC will let you do it with 3D surface objects, but not solids, and only with node editing.  Check "selector mode" for a surface object and the nodes in the selection set can have their relationship scaled, rotated or moved.  If you're determined to distort a solid like that, you'd have to perform the distortion with a surface object, explode it down to line segments and recompose them into profiles for lofting or prisming, or alternatively just check solid in properties - that'll give you a faceted solid.  I haven't seen Rob Berry's work, but generic transform doesn't offer this for 3D so far as I know.  However, I've done a screencast of how node edit can make it work.

http://screencast.com/t/0FyDLa3crDqG
« Last Edit: October 01, 2012, 08:47:14 PM by murray dickinson »

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October 01, 2012, 09:11:19 PM
#5
Murray:  Thanks so much for making that movie!  Is there supposed to be audio with it?  I did not get any audio.

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* October 01, 2012, 09:14:09 PM
#6
No, I didn't think it need audio.  I was probably humming the Muppet theme anyway!

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October 01, 2012, 09:26:14 PM
#7
Okay, I've got you now.  No, GT doesn't distort 3D objects like that; it doesn't alter the relationship between an object's features.  TC will let you do it with 3D surface objects, but not solids, and only with node editing.  Check "selector mode" for a surface object and the nodes in the selection set can have their relationship scaled, rotated or moved.  If you're determined to distort a solid like that, you'd have to perform the distortion with a surface object, explode it down to line segments and recompose them into profiles for lofting or prisming, or alternatively just check solid in properties - that'll give you a faceted solid.  I haven't seen Rob Berry's work, but generic transform doesn't offer this for 3D so far as I know.  However, I've done a screencast of how node edit can make it work.

http://screencast.com/t/0FyDLa3crDqG

Thanks Murray!

I was able to duplicate what you showed -- by tranforming the object into a surface.  Transforming to a surface informed me that I would not be able to get back to a solid -- and I can't.

I think that, while my target object has a fair amount of detail, I think I can re-Extrude the polylines there to get the desired results.!  Thanks so much!!

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* October 01, 2012, 10:01:23 PM
#8
If your object is faceted, like a polyhedron, select and right-click, in 3D properties you should be able to check solid and make it so. 

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* October 01, 2012, 10:27:33 PM
#9
Would the "Facet Edit" tool work here? See the Help or Wiki.

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John R.

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October 02, 2012, 02:32:43 PM
#10
I had a bunch of polygons that I extruded & filleted -- but I srapped the Extrusion and kept the 2D polygons.  I figured out that my whole extrusion needed to be angeled with one edge 5/8" over in "Z".  Not being able to manipulate the extrusion, and since nothing else worked, I got my result another way.  I was able to rotate the entire 2D series of polygons to the exact angle (to 5 dec places) I measured by the 5/8" offset.  Then I scaled the result to the final correct lengths.  Not very elegent, but it worked.  Now I will need to re-Extrude all my polygons (in their new plane) and re-do the 3D fillets.

I tried to use the Edit command to move these 2D items also.  I could not get the Edit tool to recognize any point outside its own workplane; nor could I change workplanes once the Edit Tool was active!

I remain somewhat frustrated with the inability of TC to be able to Skew or Distort any solid 3D object.  (I see the conversion of a solid to a TC Surface as a complete dead-end -- unless the surface can be re-formatted to an ACIS solid -- which it cannot.)  I never allow any surfaces in any of my drawings.

I am now wondering if the new smesh commands in v19 would allow me to de-select enough points in the solid to where the "cube" could be actually Skewed?

If anyone is interested, I could post this portion of my file.  Let me know.

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* October 02, 2012, 03:11:35 PM
#11
I made another screencast of switching solid to surface and back again.  If you select solid or surface and the options are greyed out in properties, explode the object once and then go back to properties.  The check buttons will be available to change the option.  If the object has facets only, the conversion won't alter its exterior at all.  If it has curved surfaces or fillets, converting to surface will turn those into faceted approximations, but you can skew a cube or polyhedron, convert it to solid and then fillet the edges you want.

http://screencast.com/t/3HhFTjgmh

I'd like to look at your file if it's posted.
« Last Edit: October 02, 2012, 03:14:21 PM by murray dickinson »

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