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How to skew a 3d object in TC2016?
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* January 10, 2019, 12:08:02 PM
Hi All,

I have a need to skew a 3d object by around 5 degrees (tiny amount really) but I am struggling to figure out how to do it :(

I found this really useful post which seemed to provide the answer:-
http://forums.turbocad.com/index.php?topic=10017.0

But on attempting this using my 2016 version, my edit tool will not allow me to highlight one side's corner edit nodes for me to then skew using the delta boxes as per the embedded videos. In the video, I think the left mouse is held and a box is drawn around the required corner edit nodes, but this doesn't do anything in my version :(

Also tried the Modify > Transform > Generic using the 'skew' option but I found this really cryptic and I couldn't get that to work either using the TC manual :(

Any help would be gratefully received,

Thank you

Adrian
* - updated with correct URL
« Last Edit: January 13, 2019, 09:27:37 AM by adrianh78 »

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* January 10, 2019, 01:14:14 PM
#1
The link you provided is a thread about computers,   Is this one the post (and video) you mean.

Are you working in Pro or Deluxe/expert.   If Pro and using ACIS objects, in the video Murray converts the object to TC surface first, then back to ACIS afterwards. This is fine for  simple objects (cube etc.), but not for anything with any curves.   Deluxe already uses TC surfaces so it should show the nodes (probably blue in colour).

For ACIS objects (in pro) one can often get away with using the facet edit tool, it takes a few extra steps as one sometimes needs to do each facet separately,  but it does depend on the object shape.

Can yo post an image of what you require skewing.     

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* January 10, 2019, 01:22:34 PM
#2
If you mean skew as in the picture, it's trivial as a TC surface edit.  Explode the object to a TC surface, use the edit tool to displace the nodes.  You can achieve different deformations using node edit selector mode, which allows relative and proportional displacement of the vertices compared to the absolute displacement that you get without selector mode. 

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* January 13, 2019, 09:15:08 AM
#3
The link you provided is a thread about computers,   Is this one the post (and video) you mean.

Are you working in Pro or Deluxe/expert.   If Pro and using ACIS objects, in the video Murray converts the object to TC surface first, then back to ACIS afterwards. This is fine for  simple objects (cube etc.), but not for anything with any curves.   Deluxe already uses TC surfaces so it should show the nodes (probably blue in colour).

For ACIS objects (in pro) one can often get away with using the facet edit tool, it takes a few extra steps as one sometimes needs to do each facet separately,  but it does depend on the object shape.

Can yo post an image of what you require skewing.   

Many thanks for the response

My apologies for the slow response, and yes! great detective work, the post you found is the one I was referring too... I will update my post so it makes sense for others in the future should they search for a similar solution..

Please see below, it is the C-hub I have designed for my model car. the picture as you look behind it, I want to slant 5 degrees to give me another option. So the top half will be 5 degrees further forward than the bottom half.

*- PS - I am using 2016 Pro
« Last Edit: January 13, 2019, 09:28:20 AM by adrianh78 »

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* January 13, 2019, 09:26:21 AM
#4
If you mean skew as in the picture, it's trivial as a TC surface edit.  Explode the object to a TC surface, use the edit tool to displace the nodes.  You can achieve different deformations using node edit selector mode, which allows relative and proportional displacement of the vertices compared to the absolute displacement that you get without selector mode.

Thanks for the reply I really appreciate it. You've lost me a little, could you drop me a link to the TurboCAD 2016 pro manual with the bit I need to review please? Thanks again

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* January 13, 2019, 09:29:58 AM
#5
Thank you wholeheartedly for the help and support - I don't find CAD easy, so I really appreciate it  :)

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* January 13, 2019, 04:38:36 PM
#6

Please see below, it is the C-hub I have designed for my model car. the picture as you look behind it, I want to slant 5 degrees to give me another option. So the top half will be 5 degrees further forward than the bottom half.


Posting the TC file would be easiest .... From what i see, What your asking can be done ... but the method depends on "How the model was created".


1 way is to separate the Bottom & Top portion and recreate the Vertical element at 5 degrees >> Then 3D Add it back together.
or
Separate Top & Bottom / Draw 5° lines at key points of bottom to top / Shift Top to end of 5° line / Node Edit Vertical portion to Top / 3D Add it back together.

OR ...
If your just trying to Turn the Whole Model 5° ....
It is done via the Rot X, Rot Y Rot Z fields.

Ensure these Fields are Ticked for viewing via ...
SELECT / RM click > Toggle 3D / Rm click > Selector 3D Properties / (Inspector Bay) Tick Rotation X Y Z

Rot X Y & Z field boxes should show up at the bottom of your screen.

Cheers
Mike


« Last Edit: January 13, 2019, 05:03:26 PM by Mike90RR »

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* January 14, 2019, 01:23:45 PM
#7
Hi Mike,

In the first instance, thank for your input, I appreciate it.

Answers in line,

Thanks

Adrian


Please see below, it is the C-hub I have designed for my model car. the picture as you look behind it, I want to slant 5 degrees to give me another option. So the top half will be 5 degrees further forward than the bottom half.


Posting the TC file would be easiest .... From what i see, What your asking can be done ... but the method depends on "How the model was created".
Will do, just need to clean it up first

1 way is to separate the Bottom & Top portion and recreate the Vertical element at 5 degrees >> Then 3D Add it back together.
I can definitely do this, and separating top and bottom halves was how I wanted to achieve the skew i.e. just skew the middle portion 5 degrees, then 3d add back together. But I haven't gone the recreate route as I felt it was labor intensive, and there should be a tool to skew it x degrees to my mind
or
Separate Top & Bottom / Draw 5° lines at key points of bottom to top / Shift Top to end of 5° line / Node Edit Vertical portion to Top / 3D Add it back together.
I think I know what you mean, but I think it would be more elegant skewing the middle section 5 degrees rather than frankensteining it

OR ...
If your just trying to Turn the Whole Model 5° ....
It is done via the Rot X, Rot Y Rot Z fields.
Rotation is no problem in the model space, it is how it comes out when printed - but thanks for the tip

Ensure these Fields are Ticked for viewing via ...
SELECT / RM click > Toggle 3D / Rm click > Selector 3D Properties / (Inspector Bay) Tick Rotation X Y Z

Rot X Y & Z field boxes should show up at the bottom of your screen.
Thanks for this also - but these controls are showing
Cheers
Mike

Thanks again

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* January 14, 2019, 01:34:01 PM
#8
If you mean skew as in the picture, it's trivial as a TC surface edit.  Explode the object to a TC surface, use the edit tool to displace the nodes.  You can achieve different deformations using node edit selector mode, which allows relative and proportional displacement of the vertices compared to the absolute displacement that you get without selector mode.

I think your post likely has my solution, but unlike the video when my TC2016 Platinum is in 'edit tool' mode I don't seem to be able to select the nodes on one face (like yours in purple on your image) in order to be able to skew with a delta displacement number.

Please see attached a box example in edit mode, note hollow edit node squares. Tried selecting with CTRL held but no joy to select multiple nodes  and it won't 'lasso select' like the video below:(

Should be dead easy like this - http://www.screencast.com/t/3HhFTjgmh - but its not with my version :(
« Last Edit: January 14, 2019, 01:43:27 PM by adrianh78 »

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* January 14, 2019, 02:25:10 PM
#9

Please see attached a box example in edit mode, note hollow edit node squares. Tried selecting with CTRL held but no joy to select multiple nodes  and it won't 'lasso select' like the video below:(

Wrong nodes,  you need to explode the object until it reads TCSurface in the selection palette (usually just once, but twice if its a native object, box, wedge etc.).  then when selected with the edit tool, it will show lots of square blue nodes.

I've still no idea of the kind of skewing you require, BUT.  Note, can you live with distortion that may be caused by moving nodes of a complex object. Like the one in your picture.  Attached is what will happen with a 5 degree movement of the top set of nodes,  because the bottom ones are fixed, skewing will alter the cross section of the object.

As Mike says separating before rotating is a good way.  One can attempt to use constraints which could accomplish the task, but constraints are difficult to use on complex objects,.

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* January 16, 2019, 10:29:14 AM
#10

Please see attached a box example in edit mode, note hollow edit node squares. Tried selecting with CTRL held but no joy to select multiple nodes  and it won't 'lasso select' like the video below:(

Wrong nodes,  you need to explode the object until it reads TCSurface in the selection palette (usually just once, but twice if its a native object, box, wedge etc.).  then when selected with the edit tool, it will show lots of square blue nodes.

I've still no idea of the kind of skewing you require, BUT.  Note, can you live with distortion that may be caused by moving nodes of a complex object. Like the one in your picture.  Attached is what will happen with a 5 degree movement of the top set of nodes,  because the bottom ones are fixed, skewing will alter the cross section of the object.

As Mike says separating before rotating is a good way.  One can attempt to use constraints which could accomplish the task, but constraints are difficult to use on complex objects,.

Wow what a post, thank you

I will have a play now and report back. Thanks so much for your effort - awesome :)

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* January 16, 2019, 11:56:54 AM
#11
@ Andy H

Many thanks for the pointers on how to skew using the Edit Tool - still cannot get my head around why I would need to exploded something which to my mind was in its simplest form any (a cube in this example).

Ironically, I think my shape was too complex to skew unlike the box (see 2.png) - please see below section of the C-Hub in Edit Tool mode; to my mind no way of skewing the whole unit 5 degrees with all those edit nodes.

So likely going with @Mike90RR suggestion of just rotating a chunk and then adding back together (see 3.png)

Thanks again Andy - and everyone else who has contributed to this I really appreciate it




« Last Edit: January 16, 2019, 12:02:53 PM by adrianh78 »

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* January 16, 2019, 04:38:37 PM
#12
The problem with distorting the part the simplistic way you describe is that you want to angle two faces but move the upper cylindrical faces, this is not one glib "skew".  Exploding curved surfaces to TC surfaces reduces them to facet approximations instead of exact geometry, also something to avoid.    You'd have made your job a lot simpler if you'd used TC's capacity for feature-based parametric modelling to build the part,  but you can directly edit it using facet editor to do what you want.  Select the part with facet editor and select all of the upper faces and move them inboard the distance you need, then select the inner face of the connecting upright and tilt it to whatever angle you want, then repeat for the outer face.  As has been suggested, post the part if you want precise advice, fluffing about with words and pictures is a time sink.

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* January 18, 2019, 11:02:36 AM
#13
Adrian,

I think your post likely has my solution, but unlike the video when my TC2016 Platinum is in 'edit tool' mode I don't seem to be able to select the nodes on one face (like yours in purple on your image) in order to be able to skew with a delta displacement number.
Also tried the Modify > Transform > Generic using the 'skew' option but I found this really cryptic and I couldn't get that to work either using the TC manual
'Selector mode' in 'node editor' has several limitations, so you can use 'Selector' tool.  Skew transform can be represented as a combination of rotations, movements and scales (i.e. this is analog of "Generic using the 'skew'"). Please note: applying the Skew matrix to the whole object will lead to distortions (as murray wrote above ).

See attachments:
  Skew using Selector.png
  Skew using Selector.mp4
  Skew using Selector_ Distorsion.png

In other words, after this Skew there will be no vertical surfaces!. Therefore, I am sure that it will not suit you.


I have a need to skew a 3d object by around 5 degrees (tiny amount really) but I am struggling to figure out how to do it :(
As I understand from the discussion, you need a more complicated procedure.
 - the part of the object must be unchanged
 - the part must be moved
 - the part must be rotated at a certain angle.
Also, we must specify the way all these parts will be connected after transformation.

It can be done in TC, but you need to use the Bend tools and Part Tree.

See attachments:
  skew.TCW
  True skew.mp4
  True skew.png

Vlad

« Last Edit: January 18, 2019, 11:19:00 AM by Vlad Veselov »

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January 18, 2019, 04:41:47 PM
#14
'Selector mode' in 'node editor' has several limitations, so you can use 'Selector' tool.  Skew transform can be represented as a combination of rotations, movements and scales (i.e. this is analog of "Generic using the 'skew'"). Please note: applying the Skew matrix to the whole object will lead to distortions (as murray wrote above ).

I'm missing something with the Conceptual Selector.

In the video "Skew using Selector.mp4", the selector is rotated independent of the object, and then the object is adjusted along the local X axis.

Which command sequence allows the Selector to be rotated in this manner?


Jeff

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TC Pro Platinum 2019, 2018, 2017, 2016 & 2015 (all with LightWorks & RedSDK) & V21
System: i7-5820K @ 3.30GHz, ASRock X99 Extreme4, 16GB DDR4-2133 RAM, Gigabyte GTX 970, Samsung NVMe SSD 950 (256GB), Windows 7 Pro (64-bit) SP1


* January 18, 2019, 05:33:27 PM
#15
I'm missing something with the Conceptual Selector.

In the video "Skew using Selector.mp4", the selector is rotated independent of the object, and then the object is adjusted along the local X axis.

Which command sequence allows the Selector to be rotated in this manner?
Jeff,

This is the main Selector functionality, it does not depend on the 2D/3D and classic/conceptual modes. Please notice the mouse cursor in the video. See: Rotation Bar (dragging with Ctrl key) https://turbocaddoc.atlassian.net/wiki/spaces/T2UG/pages/92602433/2D+-+3D+Selector

This feature allows the user to scale in any direction. Unfortunately it is not available in the 'node editor'.

Vlad
 

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* January 20, 2019, 03:47:49 AM
#16

Vlad, thank you so much for taking the time to do that, I really appreciate it.

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* January 20, 2019, 04:07:13 AM
#17
Incidentally the attached is an example of the item I need to skew by 5 degrees. It is a part for a model car, and effectively I wish to change the cars caster by 5 degree (or more) see bend in photograph below for a real life example.

I think I have some really good stuff to go on, so when I get some spare time I will play around using the techniques described within the posts.

Incidentally, you all seem on so much higher level than me at TC - are there any learning resources I can use to improve my knowledge?

Thank you, thank you, thank you - I really appreciate it
« Last Edit: January 20, 2019, 01:45:04 PM by adrianh78 »

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January 20, 2019, 05:40:38 AM
#18
Incidentally, you all seem on so much higher level than me at TC - are there any learning resources I can use to improve my knowledge?

Other than us, you mean?   ;)

Don Cheke has some useful tutorials at http://www.textualcreations.ca/.


Jeff

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TC Pro Platinum 2019, 2018, 2017, 2016 & 2015 (all with LightWorks & RedSDK) & V21
System: i7-5820K @ 3.30GHz, ASRock X99 Extreme4, 16GB DDR4-2133 RAM, Gigabyte GTX 970, Samsung NVMe SSD 950 (256GB), Windows 7 Pro (64-bit) SP1


* January 20, 2019, 05:55:35 AM
#19
Incidentally, you all seem on so much higher level than me at TC - are there any learning resources I can use to improve my knowledge?

Other than us, you mean?   ;)

Don Cheke has some useful tutorials at http://www.textualcreations.ca/.


Jeff

Thanks Jeff I really appreciate it :)

PS - this is an excellent learning resource, but didn't want to be a pain...
« Last Edit: January 20, 2019, 05:59:34 AM by adrianh78 »

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