Interior and Exterior Rendering: Different Work, Different Cost

Why an interior view and an exterior view are not interchangeable line items, what drives each, and how to brief them separately.

Developers frequently ask for a number of renders without distinguishing interior from exterior, and the two are different work with different cost drivers. Quoting them as one line produces either an overpriced exterior or an underpriced interior, and the difference is large enough to matter across a launch set.

Exterior work is dominated by context and light. The building itself is usually available from the architect's model, and the cost sits in everything around it: the landscaping, the road, the neighbouring buildings, the sky, the vegetation and the people. A convincing exterior is largely an environment build with a building in it, which is why an exterior in an established urban context costs considerably more than one on an open site.

Interior work is dominated by materials and lighting. The geometry is simple, and the cost sits in the surfaces: the floor finish, the joinery, the fabric, the reflections, the way light from a window falls across a wall. Every material has to behave correctly, and the room has to be furnished and styled, which is a set dressing exercise performed in three dimensions.

This produces a practical asymmetry. Additional exterior views from the same model are comparatively cheap, because the environment already exists and the camera simply moves. Additional interior views frequently are not, because a different room means different materials, different furniture and a different lighting setup. A quote offering five exteriors and five interiors for the same unit price is either overcharging for one or undercharging for the other.

Light behaves differently between the two and the choices are not interchangeable. Exteriors are usually rendered at dusk or in late afternoon, where a low warm sun and a deepening sky flatter the massing. Interiors are usually rendered at a time that lets window light do the modelling while interior fixtures provide warmth. Jonauskaite et al. (2020) documented consistent patterns of emotion associations with colours, which is the perceptual basis for a convention that visualisation artists arrive at by instinct.

Accuracy obligations differ too. An exterior misrepresents most easily through context, showing a view that ignores approved neighbouring development or landscaping at a maturity it will not reach for a decade. An interior misrepresents most easily through inclusion, showing furniture, appliances and finishes that are not part of the specification. Both are recurring sources of dispute and both are avoided by rendering what is specified and disclosing what is illustrative.

The commercial function differs, which should drive how many of each to commission. Exteriors sell the development and the location, and they are what appear on hoardings, in press and on the website. Interiors sell the unit, and they are what a buyer studies in the sales gallery when deciding between layouts. Poushneh (2021) found that perceived proximity to a virtual product influenced purchase intention, and for an unbuilt unit the interior is where that proximity is created.

Resolution requirements usually differ as well, and this catches projects out. Exteriors more often end up on large format output, hoardings, lightboxes, double page spreads, and therefore need substantially more pixels than a web hero. Interiors are more often studied at close range on a screen or in a brochure. Establishing the largest intended output per image before rendering, rather than after, is the difference between an image that holds at size and one that has to be redone.

Revision behaviour differs and should be reflected in the terms. An exterior revision is often a camera or a light change, which is a re-render. An interior revision is frequently a material or a furniture change, which is a rebuild of part of the scene followed by a re-render. Pricing the same revision allowance for both is a common way for archviz projects to become unprofitable.

The briefing advice for a developer is to specify them separately and to say what each image has to do. For exteriors: which elevation, what time of day, how much surrounding context, and the largest output size. For interiors: which unit type, which room, which finish package, whether furnished, and whether the view out of the window matters. A studio given those answers quotes accurately; one given a request for ten renders quotes a range.

References

Jonauskaite, D., Parraga, C. A., Quiblier, M., & Mohr, C. (2020). Feeling blue or seeing red? Similar patterns of emotion associations with colour patches and colour terms. i-Perception, 11(1), Article 2041669520902484. https://doi.org/10.1177/2041669520902484

Poushneh, A. (2021). How close do we feel to virtual product to make a purchase decision? Impact of perceived proximity to virtual product and temporal purchase intention. Journal of Retailing and Consumer Services, 63, Article 102717. https://doi.org/10.1016/j.jretconser.2021.102717