HDRI as a Light Source – Atmospheric Renderings

Have you ever been transported by a photograph? Or knew exactly how the photographer must have felt at the moment the picture was taken? Basking in the heat, shivering from the cold, feeling the noise of a celebrating city or the still of the middle of nowhere.

But what is it exactly in an image that speaks to our emotions? The setting, sure, but that can be interpreted in so many different ways. Why do we feel such a connection with some images, and less with others?

It may not be the answer for everything, but it’s no questions that there is usually one key factor: LIGHT.

Lighting isn’t just lights

Every light source has its own color, can be strongly focused or diffused over an object, and is warm or cold. We all have our own preferences – more or less – in terms of color temperature, and it can vary depending on the mood and the room.
If I’m being completely honest, I see the fresh fish from the fish counter in a much cool light than I would – say — me in the women’s dressing room. This is a place where I, as the customer, would prefer to trick myself a bit, and be wrapped up in soft, warm light. After all, that feeling is all a part of the “buy or don’t buy” decision.

Light makes the difference
Light makes the difference — that applies to the presentation of products (as in product photography), just as it does for portrait shooting and interior design. How do you want to see yourself when you look in the mirror? And in which light should the rooms in your plan appear? Source: Lodewick

Those who have a bit of knowledge regarding color temperatures can adapt it to the design of work and living spaces: cool light is stimulating and has a biological effect on our bodies. This makes it perfect for a room where cognitive services are provided. On the other hand, if someone is looking for a place to sit back and relax, they would instinctively choose a “warmer” environment.

And here’s where I finally get to the point: Such a mood can be accomplished in a rendering before you even adjust any of the parameters of your placed lights. The magic code here is HDRI.

DR, HDRI – a little background knowledge

Lighting isn’t just lights: While we might feel a bit blinded looking at the tail lights of a car in the dark, the light from an atom bomb, for example, is physically unbearable without eye protection and a direct look at the sun will damage your eyes. These variations in brightness are referred to as Dynamic Range (DR).

In short, HDRI (High Dynamic Range Image) is an image with a higher dynamic range and contrast. Richer in detail than “normal” images, these pictures can depict the wide range of brightness that we find in our natural environment.

HDRI as a light source
Such images not only look great, but they also contain valuable light information that can be used as a light source for renderings. Source: HDRI Hub

HDRI as a light source in the room planner

The OSPRay renderer in pCon.planner offers the possibility of using an HDR image as a light source for your rendering. If you’re looking to bathe your setting in fireplace lighting, you could upload an HDRI of a fireplace, volcano or sunset. If you’d prefer a cooler atmosphere, we would recommend a snowy landscape or raging river.
To do this, simply open the render dialog, choose OSPRay as your renderer and enable “HDR Light”. Now, you can load a locally-saved image. More technical advice and other detailed settings for OSPRay, for those who can’t get enough, can be found here.

Where can you find HDR images, you ask? You can find many platforms online that offer HDRIs for download. One example is HDRI-Hub.com.

A small tip with unlimited possibilities

The uploaded HDR image will not be automatically shown as a background image, but will instead influence only the illumination of the picture and, in turn, the overall mood. Of course, you can also upload the image as a background image – or even, and here’s the magic, select the background image and HDRI independently from one another. This way, you can customize your settings in a variety of ways. You determine the location of the background for your plan – the city, country, underwater, above the clouds, on the moon – and convey the mood you want with the HDRI.

HDRI as a Light Source – Atmospheric Renderings rendering pCon.planner OSPRay lighting HDRI
A different HDR image was used for each photo, but with the same settings. Left: HDRI and Background image are the same. Right: Background image is a snowy landscape, HDRI is a sunset.

The perfect rendering?

The use of HDR images allows for fast and efficient illumination of virtual scenes and easy compositing. Global “mood lighting” is easier to use than in the past, but in the end the fact still remains: the perfect rendering — just like in real-life interior decorating — requires a lot of tweaking and attention to detail. After all, the eyes see everything: products, colors, materials and light accents.

For those who are looking to become professionals in virtual lighting and high-end renderings, we’re happy to offer you individualized training! :)

And as always: we’d love to see some of your planning examples, so send them our way!

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