so I was happily working away, until translate stopped working. when i press g to translate a verticie; it doesn't move, although it gives the impression that it is.  when i press 1 and go into reference mode: it works again, and side view with 3. but in the normal camera perspective: nothing works.  please why please? I am fairly new to blender, i tried looking up a solution myself, no success.
My cursor is moving by every selection by large increments!  Normally when I use Blender, I am able to select and move objects to any coordinate. Now, all of the sudden, when I select an object or mesh the selection moves by an inch or so in each direction.  How do I reset it to normal?
Which is correct: "the below information" or "the information below"? How to pass Unicode characters as JSP/Servlet request.getParameter? Is it posible to upload file in Lists Attachments in SharePoint in custom way My friend and I have been wracking our heads with this one for the past 3 hours... We have 2 point masses, $m$ and $M$ in a perfect world separated by radius r.  Starting from rest, they both begin to accelerate towards each other. So we have the gravitational force between them as:  $$F_g ~=~ G\frac{Mm}{r^2}$$  How do we find out at what time they will collide?  What we're having trouble with is this function being a function of $r$, but I have suspected it as actually a function of $t$ due to the units of $G$ being $N(m/kg)^2$.  I've tried taking a number of integrals, which haven't really yielded anything useful.  Any guidance?  No, this is not an actual homework problem, we're just 2 math/physics/computer people who are very bored at work :) How to find $\partial\chi^2/\partial a$ where $\chi^2=\sum_{i=1}^N\dfrac{D(x_i)-a-b(x_i)^2}{\sigma_i^2}$?  My attempt: \begin{align} \dfrac{\partial}{\partial a}\sum_{i=1}^N\dfrac{D(x_i)-a-b(x_i)^2}{\sigma_i^2} &amp;= \dfrac{\partial}{\partial a}\sum_{i=1}^N\dfrac{D(x_i)-b(x_i)^2}{\sigma_i^2}-\sum_{i=1}^N\dfrac{-a}{\sigma_i^2}\\ &amp;=\sum_{i=1}^N\dfrac{D(x_i)-b(x_i)^2}{\sigma_i^2}-\dfrac{\partial}{\partial a}\sum_{i=1}^N\dfrac{-a}{\sigma_i^2}\\ &amp;=\sum_{i=1}^N\dfrac{D(x_i)-b(x_i)^2}{\sigma_i^2}-\dfrac{1}{\sigma_i^2}\cdot\dfrac{\partial}{\partial a}\sum_{i=1}^N-a\\ &amp;=\sum_{i=1}^N\dfrac{D(x_i)-b(x_i)^2}{\sigma_i^2}-\dfrac{1}{\sigma_i^2}\cdot\dfrac{\partial}{\partial a}a^N\\ &amp;=\sum_{i=1}^N\dfrac{D(x_i)-b(x_i)^2}{\sigma_i^2}-\dfrac{1}{\sigma_i^2}\cdot N\cdot a^{N-1}\\ \end{align}  Is this correct?  EDIT: As per the accepted answer, this is how I got my final partial derivative. \begin{align}             \dfrac{\partial}{\partial a}\sum_{i=1}^N\dfrac{D(x_i)-a-b(x_i)^2}{\sigma_i^2} &amp;= \dfrac{\partial}{\partial a}\Bigg[\sum_{i=1}^N\dfrac{D(x_i)-b(x_i)^2}{\sigma_i^2}-\sum_{i=1}^N\dfrac{-a}{\sigma_i^2}\Bigg]\\             &amp;=\dfrac{\partial}{\partial a}\Bigg[\sum_{i=1}^N\dfrac{D(x_i)-b(x_i)^2}{\sigma_i^2}\Bigg]-\dfrac{\partial}{\partial a}\Bigg[\sum_{i=1}^N\dfrac{-a}{\sigma_i^2}\Bigg]\\             &amp;= 0-\dfrac{\partial}{\partial a}\Bigg[\dfrac{-a}{\sigma_1^2}+\dfrac{-a}{\sigma_2^2}+\cdots+\dfrac{-a}{\sigma_N^2}\Bigg]\\             &amp;= -\Bigg[\dfrac{\partial}{\partial a}\Bigg[\dfrac{-a}{\sigma_1^2}\Bigg]+\dfrac{\partial}{\partial a}\Bigg[\dfrac{-a}{\sigma_2^2}\Bigg]+\cdots+\dfrac{\partial}{\partial a}\Bigg[\dfrac{-a}{\sigma_N^2}\Bigg]\Bigg]\\             &amp;= -\Bigg[\dfrac{-1}{\sigma_1^2}\cdot\dfrac{\partial}{\partial a}[a]+\dfrac{-1}{\sigma_1^2}\cdot\dfrac{\partial}{\partial a}[a]+\cdots+\dfrac{-1}{\sigma_N^2}\cdot\dfrac{\partial}{\partial a}[a]\Bigg]\\             &amp;= -\Bigg[\dfrac{-1}{\sigma_1^2}+\dfrac{-1}{\sigma_2^2}+\cdots+\dfrac{-1}{\sigma_N^2}\Bigg]\\             &amp;= \sum_{i=1}^{N}\dfrac{1}{\sigma_i^2}\\         \end{align} How to change file extension at runtime in Java In the Harry Potter series is it clear that magically-inclined individuals (witches/wizards) will live to be considerably older than their Muggle counterparts? From the question , it is given that Dumbledore was roughly 115 years old when he died, and at that age he hardly seemed ready to kick the bucket naturally.  With that in mind, how old will a wizard typically live to be, barring accidents or murder? How to simulate from a Gaussian copula? Suppose that I have two univariate marginal distributions, say $F$ and $G$, which I can simulate from. Now, construct their joint distribution using a , denoted $C(F,G;\Sigma)$. All the parameters are known.  Is there a non-MCMC method for simulating from this copula? Showing that $(m)\cap (n)=(\operatorname{lcm}(m,n))$ and $(m)+(n)=(\gcd(m,n))$ for any $m,n\in\mathbb{Z}$ Why do people buy stocks that pay no dividend? Before recently, Apple Inc. did not give dividend to shareholders.  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