Grasshopper Workshop at Cornell Architecture

grasshopper-workshop-poster-sept7-2009-sworkshop 1

PDF download

Source File download

  1. Leah said:


    Some of the commands weren’t available in the version on Grasshopper I’m using such as Display and Graft Tree. Is there an alternative command I could use?


    • Woo Jae said:

      Check out your grasshopper version. This tuto is based on 6.019 WIP.

  2. Daniel said:


    I am doing the tutorial, and at step01_04, and on the last step on that page I cannot get my points to come out in a curve like that? Is anyone else having this problem? Please help!

    • Woo Jae said:

      I cannot help you with just what you said. Can you explain more about your issue? Are you using 6.019?

    • tonylu said:

      Hi Woo Jae,
      I have a similar question to Daniel’s.
      Is the last step adding Multiply is what it shows on the diagram? the one shows on the diagram looks like Power (Step01_4).

      Thanks for the answer!

  3. David said:

    Thanks a lot for the informative tutorial. A few things, however.

    I was unable to get Step01_9 to work. When I would plug the Normals from the Eval into the Offset object, the end result was a positive extrusion, which extruded the surfaces the wrong direction, to the inside of the overall shape. I eventually simply plugged the random object directly into the offset, which resulted in the same issue, the offset would inevitable be in the wrong direction. I changed the random range to -1 to 0 and the offset reversed itself. I could not, however, get this to work with the normals from the evaluation of the SubSrf.

    The other issue was at the end when you used a Graft. I was able to get the result without using any grafts, simply eliminating that step. Could you let me know what the graft does in your tutorial and why it is important?

    One more thing (sorry to take so much time). In your other tutorial, you regularly connected multiple individual curves into the “Join Curves” object. When I attempted to duplicate this, it would only allow me to connect one curve or the other, thus not allowing me to finish your more advanced tutorial.

    Again, thanks for writing these, they really help augment one’s understanding of Grasshopper and Geometry creation.

    • Woo Jae said:

      Sorry not responding. That is because you did not set the offset vector reversed. Right click on ‘D’ tap on the offset object, and type in ‘-D’, which will flip the offset vector. That is the reason for all subsequent problems. And if you want to connect more than one input, just hold down shift key while you connect each piece.

  4. Greg said:

    I think you can now do evolo very well.

    : )

    • Woo Jae said:

      Greg! how are you? Your comment reminds me of that night! Your last semester is ending soon.. Ready for the real world?

  5. Ohlee said:

    Hi Woo Jae,

    when I try to download the tutorial, it stops at page 13 and the page is only half… ist this correct? thanks…ohlee

    • Woo Jae said:

      It will take some time to complete download,, it is a big file like 8mb. Did you try right click and save as option?

  6. Boris Yundelson said:

    Thank you for the tutorial its pretty amazing. The issue i am having is at the last step when i connect the 8 list items to the twisted box, all the list items except for one turn red. What i dont understand is how does list item know which vertex to use since we didnt really give it any instruction? I understand what you are attempting, to get the four vertices from the original extruded surface to connect for lack of a better word to the 4 offset vertices and form a box, but its not working for me. Any help would be greatly appreciated.
    Thank You,
    Boris Yundelson

  7. Boris Yundelson said:

    oh nevermind i figured it out, i had to change the list item boolean to true and give each list item a different integer for each vertex from 1-8 and it worked out. Thank you

  8. abigail said:

    저는 한국에서 산업디자인을 전공하는
    대학생입니다. 그래스오퍼에 대해서 구글링하다가
    많은 도움 얻고 갑니다 ㅠㅠ 코넬대에서 유학중이신거 같은데
    힘내셔서 국위선양하세요 화이팅!

  9. Hyunsoo said:

    Nice works, I’m learning so much from your web site
    thanks a lot

    from London

  10. Matt said:

    I’m having trouble with step 1_06. The points are flexing according to the reference points. The Merge is feeding in the information of the grid but when I go to connect the number of U from the U slider the SurfGrid goes red. I set the expression and made (I) true as specified. What else to do since the number of U comes from that slider and the SurfGrid is saying it is recieving 1 number (21); since my slider is on 20.

  11. Konrad said:

    Hi I’ve got a problem with step01_03.

    List is spliting only verticaly not horizontaly. When I was working on previous version, I was ok. After switching to new version list splits only verticaly.

    I have notice one small difference in new version cell is called SDivide insted of Divide, dose it make difference ?

  12. Konrad said:

    Ok made this step with litle modyfication..

    I have decoposed points and then compose again. In between I have made boolean with z component equal 0 and after this I have split the list. I hope it’ll work with rest of tutorial but for now it wokrs the same (base is out of the list).
    Anyway does anybody know what was the problem? – Why points has been selected in vertical direction ?

  13. Woo Jae said:

    Guys, sorry for not responding. Will get back to you guys soon.

  14. Konrad said:

    hi I’ve got another problem with step 1_06. I can’t create mesh out of points.

    1. Expression u+1 seems to be not enough in some cases i need to add 2 to have enough UCounts for points.

    2. Even when I have proper amount of points it doesn’t create mesh. Error says:
    “Object reference not set to an instance of an object”

  15. Lasse said:


    regarding step 4 (i’m not in your grasshopper version but the new one)

    It looks like you use the multiply button twice but get 2 different components (name and in/out puts? Also a translation of button names to new grasshopper would be awesome!!

    Thank you so much for the tutorial!

    • Lasse said:

      I found the file and borrowed the old buttons.. so no problems:)

  16. Excellent posting. You’re beyond doubt an expert when it comes to this writing. It is just the first time I visited your site and frankly speaking it succeeds in making me visit here time and again.And yes i have digg your site .

Leave a Reply to Konrad Cancel reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.