1.1 Introduction to modelling and rendering software

Modelling and rendering software allows interior designers to build three-dimensional digital models of spaces and turn them into realistic images, animations and virtual walkthroughs. Modelling is the process of creating the 3D geometry of walls, floors, ceilings, furniture, fittings and decorative items, while rendering is the process of calculating how that model looks when materials, lighting and a camera view are applied, producing a finished picture. Together they let designers test ideas, check proportions, compare finishes and show clients exactly how a space will look before any money is spent on construction. Example: before refurbishing a boutique hotel's rooftop restaurant, the designer models the space with its pergola, bar and seating, applies timber, stone and fabric materials, sets evening lighting and renders views that convince the owners to approve the scheme.

Key terms in modelling and rendering

Modelling and rendering use a set of terms that appear throughout software menus, tutorials and discussions with visualisers. Understanding them makes it easier to learn any program. Example: a visualiser preparing images for a real estate developer's show apartment talks about polygon counts, materials, HDRI lighting and render resolution, all of which the designer must follow.

Terms

• 3D model: A digital representation of objects with length, width and height that can be viewed from any angle.
• Vertex, edge and face: The points, lines and flat surfaces that make up a polygon model.
• Mesh: A collection of vertices, edges and faces forming the surface of an object.
• Material: The digital description of a surface, such as its colour, texture, shine and transparency.
• Texture map: An image applied to a surface to show patterns such as wood grain, fabric or tiles.
• Light source: A digital light, such as the sun, a lamp or a spotlight, that illuminates the scene.
• Camera: A virtual viewpoint that defines what part of the model is shown and from which angle.
• Render: The final image calculated from the model, materials, lights and camera.
• Render engine: The part of the software that calculates the image, such as V-Ray, Corona or a real-time engine.
• Resolution: The size of the rendered image in pixels, such as 1920 × 1080.

Approaches to 3D modelling

Different methods are used to create 3D geometry, each suited to particular kinds of objects. Interior designers often combine them in one project. Example: a designer for a co-operative bank's new branch builds walls and counters with precise solid and parametric modelling, and the curved reception sculpture with polygon modelling.

Rendering concepts

Rendering turns a model into an image by simulating how light interacts with surfaces. The quality of a render depends on the materials, lighting, camera settings and the render engine used. Example: an architectural practice preparing visuals for a private school's library balances daylight from tall windows with warm artificial lighting to show the space during an evening study session.

Elements that affect a render

• Materials and textures: Realistic materials with correct reflections, roughness and scale make surfaces convincing.
• Lighting: Daylight, sky lighting and artificial lights create mood and show forms through light and shadow.
• Camera settings: Viewpoint, focal length and height control composition and how natural the view looks.
• Global illumination: Calculation of light bouncing between surfaces gives soft, realistic lighting.
• Resolution and quality settings: Higher resolution and sampling give sharper, cleaner images but take longer.
• Post-production: Adjusting colour, contrast and adding entourage in image-editing software after rendering.

Real-time and offline rendering compared

Worked example: render time for an animation

Number of frames = duration in seconds × frames per second

Total render time = number of frames × time per frame

A 20-second walkthrough of a wellness centre is rendered at 25 frames per second, with each frame taking 45 seconds.

Number of frames = 20 × 25 = 500 frames

Total render time = 500 × 45 = 22,500 seconds

Total render time = 22,500 ÷ 3,600 = 6.25 hours

The modelling and rendering workflow

Modelling and rendering follow a sequence of stages from information gathering to final output. Following the workflow avoids rework, such as remodelling after materials are applied. Example: a visualisation studio working for a hospice follows the same nine stages for every project so that deadlines can be planned accurately.

1. Gather information: Collect drawings, measurements, photographs, material samples and the client brief.
2. Set up the project: Create the file with correct units, scale and folder structure.
3. Model the space: Build walls, floors, ceilings, openings and fixed elements from the drawings.
4. Model or insert furniture and fittings: Add furniture, fittings and décor from libraries or model them.
5. Apply materials and textures: Assign realistic materials and adjust texture scale and orientation.
6. Set up lighting: Add daylight and artificial lights to match the design intent.
7. Set cameras and views: Place cameras for the main views and test compositions.
8. Render and post-produce: Render the images, then adjust colour and add finishing touches.
9. Review and revise: Check images with the client or team and make changes before final output.

Applications of modelling and rendering in interior design

Modelling and rendering support many tasks beyond producing attractive pictures. They help designers make better decisions and communicate clearly at every stage. Example: a mobile network operator uses rendered views of its proposed retail stores to agree the layout with branch managers before fit-out starts.

Applications

• Concept development: Testing layouts, forms and colour schemes quickly in 3D.
• Client presentations: Showing realistic views so clients understand and approve designs.
• Material and finish selection: Comparing different finishes and colours on the same model.
• Lighting design: Studying daylight and artificial lighting effects before installation.
• Space checking: Checking proportions, sightlines, clearances and furniture fit in three dimensions.
• Marketing: Producing images and walkthroughs for brochures, websites and property sales.
• Joinery and furniture design: Developing custom pieces and extracting drawings for manufacture.
• Virtual reality walkthroughs: Letting clients experience the space at full scale before it is built.

Benefits and limitations