Map a geometry on a surface (grasshopper beginner)

Hi guys!

I'm quite new on grasshopper, and I'm trying to map a geometry on a irregular surface, avoiding that the geometry will be distorted where the surface is smaller.

I searched on the forum and I manage to achieve this result (see image), but as you can see for some reasons the geometry is not rotated in the same direction. I would like to achieve the result in the second image.

Thanks a lot!

Attachments:

geometry on surface 15 oct 2017.3dm, 306 KB
geometry on surface 15 oct 2017.gh, 8 KB

Replies to This Discussion

Permalink Reply by chiar molino on November 11, 2017 at 12:52am

I can't see your complete definition because He said that that are object not recognizable. =( can you tell me where I can download advanced surfaces tools ?? because that 's the problem , you used this plug in =)

Permalink Reply by Birk Binnard on November 11, 2017 at 1:55am

Gosh, I don't see why you can't see everything. I don't think there are any non-GH components in the script. Over time I've tried a bunch of different GH add-ons, and I have de-installed almost all of them. I re-saved the file again to hopefully this one will work for you.

Attachments:

chiar1.gh, 17 KB

Permalink Reply by Markku on November 11, 2017 at 3:56am

Advanced surface tools can be found from Food4rhino

Permalink Reply by Joseph Oster on November 11, 2017 at 7:00am

It's still there. This is why I try to avoid plugins. Not that they can't be useful but that code isn't as easily shared. What is so advanced and special about a sphere or cylinder?

Permalink Reply by Birk Binnard on November 11, 2017 at 8:08am

Thanks for pointing out the problem Joseph. I'm not sure I could have found it on my own, and I agree that plugins can complicate things. I apologize for being so naive, but I thought Sph and Cyl were part of basic Grasshopper:

https://rhino.github.io/components/surface/sphere.html

I did install Tom's ASTools plugin once upon a time, but I don't recall why I did that. Apparently the ASTools plugin has its own Sph & Cyl components. I guess GH doesn't bother looking for a 2nd component of the same name. C'est la vie.

At any rate, I took ASTools out and substituted the GH components instead. These are actually better because their output does not require a subsequent Join to make them usable by SDiff. Here's hoping the attached file will work OK.

Attachments:

chiar2.gh, 16 KB

Permalink Reply by Joseph Oster on November 11, 2017 at 9:16am

Works now. That button shape you are morphing is pretty cool but the cylinder appears to be unnecessary?

Permalink Reply by Birk Binnard on November 11, 2017 at 9:52am

Thanks for verifying it works for someone other than me.

The cylinder is there to turn the sphere into a hemisphere. It just whacks off the bottom half of the sphere. I did this because otherwise the back side of the sphere (back means when it is morphed onto the vase shape) extends too far inwards and makes a hole in the vase. Originally I wanted to do as you suggested - make buttons on the vase's outside surface. But I had trouble getting the proper degree of thickness for the vase shape and the button shape - the buttons kept extending all the way through the vase. So I gave up and decided to use them as cutters - which is how the holes came into being.

I finally came up with a reasonable relationship between button height and vase thickness, and that's what I am printing now:

As you can see there is no twist this time - I just thought the buttons themselves looked fancy enough on their own.

One thing that I am still confused about: the sliders that control the button scaling work in reverse - to make the buttons larger, I have to decrease the slider values, and vice-versa. I'm guessing this has something to do with how SMorph works, but it is surely a confusing situation.

Permalink Reply by Joseph Oster on November 11, 2017 at 10:14am

What a cool machine!

I'm still not seeing the point of the cylinder...? If you want hemispherical bumps, why not just cut the sphere in half and cap it?

As to the scaling, I can explain that. The 'R (Reference)' input to 'SrfMorph' is expecting a 'BBox (Bounding Box)' and generating one internally based on the scaled "button". If you look back at earlier code, you'll see that I was explicitly scaling a 'BBox' around the geometry. This is a reference box for the morph so as you scale it larger in XY, it creates space around the button; that box space is what gets morphed, so to speak, along with the geometry inside it. So the bigger you scale it, the more space there is around the button on each target subsurface ('SrfSplit' output).

Permalink Reply by Birk Binnard on November 11, 2017 at 10:36am

3. That's a great explanation Joseph - thanks. I had not thought about the bounding box concept at all, but your explanation makes it very clear.

2. Since I am a totally self-taught amateur with GH I typically use brute force techniques to do things. I guess I could have split the sphere with an XY plane, but doing doing that would then require picking the top half and capping that. It just seemed simpler to whack off the bottom.

1. My printer is a nice one for sure - it's a delta style which is far less common than the standard Cartesion variety. 3D printers occupy a whole universe of their own, so I did a fair amount of research before choosing mine: http://birkbinnard.com/blog/my-printer-the-atom2/

Permalink Reply by Joseph Oster on November 11, 2017 at 10:52am

If you want hemispherical bumps, why not just cut the sphere in half and cap it?

Here's how I would do it:

Notice the explicit 'BBox', which makes things clearer if you actually look at it while scaling (disable 'SUnion' while adjusting parameters!).

Also notice that I removed the "Thickness" slider from 'Scale NU (Z)' and replaced it with the yellow group that defines a domain for 'SrfMorph (W)' with 'depth' and 'height' sliders. 'depth' is a slightly negative value to ensure that it's buried enough for 'SUnion' to succeed.

P.S. Try by-passing 'Scale NU' and connect 'BBox' directly to 'SrfMorph R' input.

Permalink Reply by Birk Binnard on November 11, 2017 at 2:59pm

Yes, that does make the bump scaling much more intuitive - thanks. As I said, the whole concept of boundary boxes is new to me so I'll have to do some further research on that. Thanks again for your help with this.

Permalink Reply by Joseph Oster on November 11, 2017 at 4:36pm

Also notice that I removed the "Thickness" slider from 'Scale NU (Z)' and replaced it with the yellow group that defines a domain for 'SrfMorph (W)' with 'depth' and 'height' sliders. 'depth' is a slightly negative value to ensure that it's buried enough for 'SUnion' to succeed.

OH NO, NOT AGAIN!! The file I posted doesn't match the screen shot and I forgot to save it. Here it is again, with 'depth' and 'height' sliders; hope I didn't lose any other details.

Attachments: