as for Multiplication instead of Multiply

Replies to This Discussion

Permalink Reply by Jesus Galvez on February 26, 2013 at 1:10am

I think depending on the version of grasshopper that you're using you can't input lines as vectors in components, because lines they are different things:

lines start and end at two points,

vector are defined by having a magnitude (length) and direction, hence unless specified they don't act in any specific point. 

Try to see if you still get the error by decomposing the line in start and end points, and building a two point vector from these points. 

Permalink Reply by Masa　Nak on February 26, 2013 at 2:37am

Thank you for your advice Jesus Galvez!

I understand your precise explanation but I can't get any clue how to arrange Decompose and Vector 2pt after PPX...
Can you suggest me example?

Permalink Reply by Jesus Galvez on February 26, 2013 at 5:00am

Sorry, I think I misled you. When I said "decomposing the line in start and end points", I meant that you use the [End Points] component to get the start and end points of the line. Then use the [Vector 2Pt] component.

What version of gh are you using? I can't find the [Vector X F] component you are using in my version (0.9.0014), which I think is the last build. 

Permalink Reply by Masa　Nak on February 26, 2013 at 8:18am

Thank you very much! They perfectly work!
I'm using newest version 0.9.0014 same as you and Multiply component included in the tutorial zip file I downloaded.

Thank you so much.

Permalink Reply by David Rutten on February 26, 2013 at 4:13am

There are three flavours of vector multiplication:

• Vector * Number (or Number * Vector). This is handled now by the regular multipication component.
• Vector · Vector (this is called the Dot Product). There is a special Dot Product component but the regular Multiplication can also handle this.
• Vector ┴ Vector (this is called the Cross Product). There is a special Cross Product component. The Cross product does not work if the vectors are (anti)-parallel or if at least one of them is zero-length.

--

David Rutten

david@mcneel.com

Poprad, Slovakia

Permalink Reply by Masa　Nak on February 26, 2013 at 8:22am

Thank you very much for your reply.

I just have started Grasshopper 2 months ago and am still beginner.

What does each symbol mean *,· ,┴?

Permalink Reply by David Rutten on February 26, 2013 at 9:03am

The * is a typical symbol representing multiplication. The dot is also often used to indicate multiplication but it specifically means Dot Product when applied to vectors. The upside-down T is the symbol for Cross Product, mathematicians also often use ×.

--

David Rutten

david@mcneel.com

Poprad, Slovakia

Permalink Reply by Masa　Nak on February 26, 2013 at 9:34am

Okay, now I understand it!

Thank you so much for the helpful great lecture!