This is a semi-duplicate of this question I think, but the answers provided there don't seem to work for me with 3D pictures.
I'm inputting a tikz picture into a beamer poster, but I think that part of the process is irrelevant, although I can include it if it's not.
My tikz picture looks like this: (spiral.tex)
\documentclass{standalone}
\usepackage{tikz}
\usepackage{tikz-3dplot}
\usetikzlibrary{decorations.pathmorphing}
\usetikzlibrary{arrows}
\usetikzlibrary{3d}
\tikzset{>=latex}
\begin{document}
\tdplotsetmaincoords{60}{60}
\tdplotsetrotatedcoords{0}{20}{70}
\begin{tikzpicture}[tdplot_rotated_coords,scale=0.5, decoration={coil}]
\draw [decorate, decoration={aspect=0.3, segment length=3.1mm, amplitude=3mm}, color = red] (0,0) --(2.6,0);
\draw [->, red] (2.6,0)--(2.6,-0.5);
\draw [decorate, decoration={aspect=-0.3, segment length=3.1mm, amplitude=-3mm}, color = blue] (-0.4,-3) -- (2.2,-3);
\draw [->, blue] (2.2, -3)--(2.3, -2.5);
\draw [->] (-0.25, -1.5)--(2.75, -1.5) node[right] {$\bf k$};
\draw[->, ultra thick, red] (4.5, 0.75)--(4.32, -0.5);
\draw[->, ultra thick, blue] (3.75, -3.75)--(3.91, -2.5);
\end{tikzpicture}
\end{document}
If you were to compile that you'd find a large area of whitespace extending off to the edge of the picture. This causes problems when I use
\begin{figure}
\centering
\begin{subfigure}[c]{0.3\textwidth}
\input{Figures/Tikz/spiral.tex}
\end{subfigure}
~
\begin{subfigure}[c]{0.3\textwidth}
\input{Figures/Tikz/another3dtikzpicture.tex} %just an example of what I want to do with the tikz picture
\end{subfigure}
\end{figure}
in my beamer poster.
I tried some of the suggestions in that other question that I linked to but they don't seem to work. I can insert \useasboundingbox (-1, -4) rectangle (5, 1); at the beginning of the picture but it doesn't do anything. I've checked that the box is in the right place by drawing it first.
Also using the command \draw [blue] (current bounding box.south west) rectangle (current bounding box.north east); to find my current bounding box gives me an error: ! Dimension too large.
Are these problems particular to drawing in 3D or particular to my code? Is there anything I can do about it?
Previously I've just compiled my tikz picture as an article and used \includegraphics[clip, trim = l b r t]{spiral.pdf} but that's not very satisfactory.
Thanks.

mwepackage or comment out those lines, I guess. – Malipivo Apr 16 '14 at 11:22\tdplotset*(twice) andtdplot_rotated_coordsand I have got no white space around the figure but I probably got 2D graph. – Malipivo Apr 16 '14 at 13:26\usetikzlibrary{3d}(no need for it in this example), so it looks thattikz-3dplotis the key. – Malipivo Apr 16 '14 at 13:33