Is the surface normal gradient a vector or a scalar?

sharonyue · September 12, 2013, 09:12

Hi guys,

According to Rusche's thesis page 82,it said:

$\nabla _f^ \bot \phi = \vec n \cdot {\nabla _f}\phi$

So we know that the surface normal gradient is a vector.

But via the other paper it said:
$\underbrace {\nabla _f^ \bot \phi \left| {{{\vec S}_f}} \right|}_{vector} = \underbrace {{\nabla _f}\phi \cdot {{\vec S}_f}}_{scalar}?????$

Whats going on? Thanks in advance...

sharonyue · September 12, 2013, 09:14

Sorry, my bad, the last term in the paper is a vector..So face normal gradient is a vector. It works.

September 12, 2013, 09:12	Is the surface normal gradient a vector or a scalar?	#1
sharonyue Senior Member Dongyue Li Join Date: Jun 2012 Location: Beijing, China Posts: 838 Rep Power: 17	Hi guys, According to Rusche's thesis page 82,it said: $\nabla _f^ \bot \phi = \vec n \cdot {\nabla _f}\phi$ So we know that the surface normal gradient is a vector. But via the other paper it said: $\underbrace {\nabla _f^ \bot \phi \left\| {{{\vec S}_f}} \right\|}_{vector} = \underbrace {{\nabla _f}\phi \cdot {{\vec S}_f}}_{scalar}?????$ Whats going on? Thanks in advance...

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September 12, 2013, 09:14		#2
sharonyue Senior Member Dongyue Li Join Date: Jun 2012 Location: Beijing, China Posts: 838 Rep Power: 17	Sorry, my bad, the last term in the paper is a vector..So face normal gradient is a vector. It works.