If a geometry $��$ is isomorphic to the residue of a point $A$ of a shadow geometry of a spherical building $��$, a representation $\varepsilon_��^A$ of $��$ can be given in the unipotent radical $U_{A^*}$ of the stabilizer in $\mathrm{Aut}(��)$ of a flag $A^*$ of $��$ opposite to $A$, every element of $��$ being mapped onto a suitable subgroup of $U_{A^*}$. We call such a representation a unipotent representation. We develope some theory for unipotent representations and we examine a number of interesting cases, where a projective embedding of a Lie incidence geometry $��$ can be obtained as a quotient of a suitable unipotent representation $\varepsilon_��^A$ by factorizing over the derived subgroup of $U_{A^*}$, while $\varepsilon^A_��$ itself is not a proper quotient of any other representation of $��$.

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