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The family of complex projective surfaces in projective three space of degree$d$ having precisely $\delta$ nodes as their only singularities has codimension$\delta$ in the linear system of surfaces of degree $d$ for sufficiently large$d$ and is of degree$N_{\delta,complex}(d)=(4(d-1)^3)^\delta/\delta!+O(d^{3\delta-3})$. Inparticular, this number is polynomial in $d$.  By means of tropical geometry, we explicitly describe$(4d^3)^\delta/\delta!+O(d^{3\delta-1})$ surfaces passing through a suitablegeneric configuration of $n=\binom{d+3}{3}-\delta-1$ points in projective threespace. These surfaces are close to tropical limits which we characterizecombinatorially, introducing the concept of floor plans for multinodal tropicalsurfaces. The concept of floor plans is similar to the well-known floordiagrams (a combinatorial tool for tropical curve counts): with it, we keep thecombinatorial essentials of a multinodal tropical surface which are sufficientto reconstruct the surface.  In the real case, we estimate the range for possible numbers of realmulti-nodal surfaces satisfying point conditions. We show that, for a specialconfiguration $w$ of real points, the number $N_{\delta,real}(d,w)$ of realsurfaces of degree $d$ having $\delta$ real nodes and passing through $w$ isbounded from below by $(\frac{3}{2}d^3)^\delta/\delta! +O(d^{3\delta-1})$.  We prove analogous statements for counts of multinodal surfaces in $P^1\timesP^2$ and $P^1\times P^1\times P^1$.

Tropical floor plans and enumeration of complex and real multi-nodal surfaces