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Shear tool and isometric question - grit - 11-05-2018

When I create any shape, for example rectangle or circle, and then use shear tool, how can I know what is perfect isometric transform ?

I use shear magnitue along Y but I never know what is true isometric value of it.


RE: Shear tool and isometric question - rich2005 - 11-05-2018

I could be wrong but I do not think you can be definite. Unlike the paint tool where shift-ctrl constrains drawing to 15° increments the shear tool does not work that way. Then it depends on the view.

[Image: 4qdAem4.jpg]

Cube A not possible by shear alone, it takes an initial shear (and guesswork) then a rotate. Cube B could be sheared in place but without that iso template no real way of knowing the angle. A circle is even worse.

Edit: Strictly A is isometric and B is (I think) dimetric, however it still follows the sides parallel, angle 30° principle

If you need to make iso drawings a CAD application is advisable. I use LibreCAD (occasionally), not bad and it is free.


RE: Shear tool and isometric question - grit - 11-05-2018

Thank you. I'll check LibreCAD.

How did you get these red lines in the background ?


RE: Shear tool and isometric question - rich2005 - 11-05-2018

It is an isometric grid generated by Inkscape and exported as a svg file - so it is a path.

With an image in place. Open in Gimp by: right click in paths dialogue, select Import path, find the svg file, open it, make it visible. Since it is a path it shows up over any layer, can be scaled to any size, only temporary to aid construction.

Attached to play with, remember to unzip it.

edit: had to look it up but Ofnuts has a plug-in to generate various grids as paths. The iso is equivalent to 'triangles' with a vertical orientation.
https://sourceforge.net/projects/gimp-path-tools/files/scripts/path-shaped-grid-0.0.py/download


RE: Shear tool and isometric question - Espermaschine - 11-05-2018

Inkscape has an Isometric Projection extension.

Here is an interesting article on the subject:
https://design.tutsplus.com/tutorials/working-with-orthographic-projections-and-basic-isometrics--vector-893


RE: Shear tool and isometric question - grit - 11-05-2018

(11-05-2018, 05:57 PM)rich2005 Wrote: edit: had to look it up but Ofnuts has a plug-in to generate various grids as paths. The iso is equivalent to 'triangles' with a vertical orientation.
https://sourceforge.net/projects/gimp-path-tools/files/scripts/path-shaped-grid-0.0.py/download

I placed in plug-ins folder, restarted but can't see this plug in.


RE: Shear tool and isometric question - rich2005 - 11-05-2018

You got path-shaped-grid-0.0.py (size 10645 B)

Well buried in the menu Filters -> Render -> Paths -> Shape Grid

Works here: https://i.imgur.com/L9gpB40.jpg


RE: Shear tool and isometric question - grit - 11-05-2018

(11-05-2018, 06:56 PM)rich2005 Wrote: You got path-shaped-grid-0.0.py (size 10645 B)

Well buried in the menu Filters -> Render -> Paths -> Shape Grid

Works here: https://i.imgur.com/L9gpB40.jpg

Thank you. It works. Super buried. These Ofnuts plug-ings should be implemented in official build because they're so useful.

How can I turn this triangular grid viewport on and off?


RE: Shear tool and isometric question - rich2005 - 11-05-2018

(11-05-2018, 07:48 PM)grit Wrote: How can I turn this triangular grid viewport on and off?

It is a path. Go to the paths dock and toggle visibility on/off


RE: Shear tool and isometric question - Krikor - 03-23-2022

(11-05-2018, 05:57 PM)rich2005 Wrote: It is an isometric grid generated by Inkscape and exported as a svg file - so it is a path.

With an image in place. Open in Gimp by: right click in paths dialogue, select Import path, find the svg file, open it, make it visible. Since it is a path it shows up over any layer, can be scaled to any size, only temporary to aid construction.

Attached to play with, remember to unzip it.

edit: had to look it up but Ofnuts has a plug-in to generate various grids as paths. The iso is equivalent to 'triangles' with a vertical orientation.
https://sourceforge.net/projects/gimp-path-tools/files/scripts/path-shaped-grid-0.0.py/download

Ohhh this is what I was looking for!  Big Grin

I even found a video explaining how to create isometric grids in Gimp, but this plugin definitely does exactly what I wanted and very easily (actually it became easy after Rich2005's tip "The iso is equivalent to 'triangles' with the vertical orientation").

Thanks a lot guys!