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CAD Forums => CAD General => The Third Dimension => Topic started by: kdub_nz on April 30, 2016, 09:58:37 PM

Title: Blend 2 solids at edge
Post by: kdub_nz on April 30, 2016, 09:58:37 PM
I'm wondering if I've forgotten something ....

I needed to blend adjacent solids (representing steel plates).
Currently I'm using some code I've written to query the complimentary dihedral angle for the plate edges, divide it by 2 and add that value to the clipboard in code.
Then I apply a taper manually to each edge using the value on the clipboard for the taper angle.

I'm wondering if there is a built in command I've missed to do this process .

Here's a ToDo and a DonePreviously piccy to help visualise the product.

added for the inquisitive :
The assembled petals represent the facets of a square to round transition chute.
The petals are flat rather than conical because they will have flat removable wear plates bolted inside to protect the chute walls from the abrasive product.
Each of the crease line will be 'pressed' on the wall plate.


Regards,
Title: Re: Blend 2 solids at edge
Post by: SEANT on May 01, 2016, 06:16:21 AM
I know I may be missing something about the starting parameters, or the necessary end result, but does this sequence of commands help at all?
Title: Re: Blend 2 solids at edge
Post by: ChrisCarlson on May 02, 2016, 08:01:33 AM
I would do the loft / thicken method as looking at your screen shot, you can easily fix the outside but the inside has two vertices instead of 1.
Title: Re: Blend 2 solids at edge
Post by: mjfarrell on May 02, 2016, 10:18:00 AM
I wonder if an interference surface would be what you are after?


Or even if UNION would not resolve those gaps?


Title: Re: Blend 2 solids at edge
Post by: kdub_nz on May 02, 2016, 12:11:51 PM

I'll have a further play with loft and thicken, when I get some spare time.

I had tried that but may have missed some of the nuances.


MJ,
UNION does not add material, it joins what is there.
How would an interference surface help me ?

Thanks for the input.
Title: Re: Blend 2 solids at edge
Post by: mjfarrell on May 02, 2016, 12:15:48 PM

I'll have a further play with loft and thicken, when I get some spare time.

I had tried that but may have missed some of the nuances.


MJ,
UNION does not add material, it joins what is there.
How would an interference surface help me ?

Thanks for the input.

The interference surface might fill in the gaps...

I was also considering a procedural method, of the nature of how they will have to actually make the thing...
either by bending or welding plates together.

Will try to post example...
Title: Re: Blend 2 solids at edge
Post by: kdub_nz on May 02, 2016, 12:22:03 PM
Here's a geometry template for anyone who wants to play.
I've saved back to ac2007.

Title: Re: Blend 2 solids at edge
Post by: kdub_nz on May 02, 2016, 12:27:02 PM

I was also considering a procedural method, of the nature of how they will have to actually make the thing...
either by bending or welding plates together.



As stated in the first post, the plates are pressed ( bent) the dihedral ranges from 150 to 170 degrees

I do need the petals as separate solids but I can slice the crease lines if necessary.
Title: Re: Blend 2 solids at edge
Post by: mjfarrell on May 02, 2016, 01:12:58 PM
this is the procedural way...

square to round...

draw 1/4 each square and round section

divide into desired number of 'bends' to achieve shape transition

offset plate thickness...

draw 3dfaces

convert to mesh

union them into 3d solids...

a bit tedious, however appears to give proper geometry for each plate making up the square to round transition....
Title: Re: Blend 2 solids at edge
Post by: kdub_nz on May 02, 2016, 01:29:03 PM
Michael, I assume you know nothing of steel fabrication.
Why are you twisting the plates ?

Title: Re: Blend 2 solids at edge
Post by: mjfarrell on May 02, 2016, 02:11:48 PM
Michael, I assume you know nothing of steel fabrication.
Why are you twisting the plates ?

If one is going from a flat edge to a circular edge...there will be some twist
or one will need to use triangular sections to fill between...

(http://www.rockwelder.com/SheetMetal/sqtr1.jpg)
Title: Re: Blend 2 solids at edge
Post by: mjfarrell on May 02, 2016, 02:13:38 PM
Michael, I assume you know nothing of steel fabrication.
Why are you twisting the plates ?

From the limited view in your original post...it looks as if you are also not using a standard development for square to round...
Title: Re: Blend 2 solids at edge
Post by: kdub_nz on May 02, 2016, 02:18:19 PM
Sheet metal work is different to structural steel where the plates have a significant thickness.

If you had looked at the template I provided you would have seen the methodology involved.

Read my first post again. There is an explicit requirement for flat planar petals.

That aside, thanks for your input.
Title: Re: Blend 2 solids at edge
Post by: mjfarrell on May 02, 2016, 02:49:10 PM
I just grabbed your geometry template...Pretty sure IF I use similar methods as with mine, the petals will also appear to be twisted....only they will just be tangent to the arcs in those decreasing radii....
Title: Re: Blend 2 solids at edge
Post by: kdub_nz on May 03, 2016, 01:51:00 AM
Just for info :
This is what it looks like without the wear plates fitted (bolted)  inside.

and a flat template of one of the corners
.... and a dwg file.
Title: Re: Blend 2 solids at edge
Post by: Bryco on May 14, 2016, 01:55:25 PM
LOFT no Bueno. extrude good
Title: Re: Blend 2 solids at edge
Post by: ribarm on May 15, 2016, 06:11:52 AM
If you're interested in lisp routine, you can found it here on WWW at cadtutor.net...

P.S. I only by accident run into this topic... Perhaps now it's too late, but just FYI... I've coded this long time ago :
http://www.cadtutor.net/forum/showthread.php?67874-LISP-routine-to-develop-square-to-round-transition/page2&p=#16

HTH, M.R.
Title: Re: Blend 2 solids at edge
Post by: kdub_nz on May 15, 2016, 08:39:15 AM
Thanks Marko.

I've had something similar myself.


//--------

Thanks Bryce.

Imagine a big sheet of thick plate.
Press the plate at the crease lines.
The edges will stay normal to the face and appear to twist at the transition at the bend.
The front and back faces will stay the same size (in length)  as the  template.

Regards,
Title: Re: Blend 2 solids at edge
Post by: Bryco on May 15, 2016, 10:32:28 AM
Kerry, on a side point (as in interested in the process):
1)you have drawn your crease lines in the center of the plate, does the machine automagically allow for creep?
I was guessing something like 6mm plate due to the size of the holes.
2) I guess you need to input the bend angle at each crease, thus the code.
3) there is no bevel on the tops and bottoms