Let $\theta$ be a closed $(1,1)$-form and let $\mathcal{X}$ be a determination of $\theta$. Then each $\theta$-psh model function $\varphi\in\mathcal{D}(X)$ is a uniform limit on $X$ of functions of the form $\tfrac{1}{m}\log|\mathfrak{a}|$ with $m\in\mathbf{N}^{*}$ and $\mathfrak{a}$ a vertical fractional ideal sheaf on $\mathcal{X}$.