Managing scene variations in complex simulations with Ocean™

Introduction

Ocean™ Light Simulator is a ray-tracing software that computes the light emitted in a 3D scene using the laws of geometric optics to generate physically true, predictive virtual images for engineering applications, including complex architectural projects.

In this article we will cover the Ocean™ workflow and its file management. Understand the main structure required to create a scene and run a realistic simulation. Explore the difference between opening and importing a scene. Finally, learn how to optimize and manipulate it to create variations with multiple configurations.

As an example, we’ll look at how to handle a simple physically true architectural scene.

The approach contrasts merging and external linking methods, emphasising strategic file handling and the importance of organised libraries and project segmentation for efficient management.

Focusing on a practical architectural example, we explore the essential and optional elements of an Ocean™ project. Understanding the critical components such as light sources, sensors and scene organising parameters is crucial for successful and physically true simulations.

From concept to simulation: Creating a physically true scene with Ocean™:

An Ocean™ project is made up of both essential and non-essential (optional) elements. If one of the indispensable elements is missing, then the simulation calculation will not be able to run.

The mandatory elements for a functional simulation in Ocean™ are as follows:

a light source
- environment: the light source comes from an HDR/EXR file “envmap” (panorama photo) or a procedural sky (Preetham-Wilkie, Hosek-Wilkie, Perez Sky)
- emitter: the light source comes from an object with emissive (energy-emitting) properties
a sensor (camera/instrument): position and orientation of the view with capture parameters

scene organization parameters (setup)
- Indicates the sensor used for simulation (define instrument)
- Indicates the environment used for the simulation (define environment)
- Indicates the CAD scene structure used for simulation (define layerset)

If not filled in, the necessary elements will block the simulation. For other elements, they will not prevent the simulation if they are not present.

In most cases, the simulation of a 3D scene requires CAD (3D geometries) as well as materials. But it’s also possible in Ocean™ to simulate complex calculations that don’t require CAD (such as data analysis, measurement…). For more insights about this topic, read our article on Ocean™ ’s measurement virtual tools .

When exporting a CAD scene (from 3dsmax or Rhino) to Ocean™, two files are created:

Exported_file.ocxml
- Contains all Ocean™ information as well as cameras, environments, materials, layers, setup ….
Exported_file-mesh.ocbin
- Contains CAD data only (3D geometries, material assignments, UVs)

Opening vs. importing in Ocean™: What is the difference?

Opening, editing and saving Ocean™ scenes: Best practices

To load a CAD scene in Ocean™, we open an ocxml file (scene data and parameters) associated with an ocbin file (scene geometries). If we make changes to this scene in Ocean™ (material, environment, …) and wish to keep these changes, then we save the project from Ocean™. This means that we overwrite the original ocxml file. Let’s imagine we want to update some geometry in the CAD software, so we export this CAD back to the ocxml file we originally exported in order to update it. We then overwrite all the modifications we have previously made in Ocean™.

Keeping Your Ocean™ scene organized

That’s why it’s important not to work directly on the exported files, but rather to work in parallel with them. The method consists in creating an empty scene from Ocean™ into which we’ll import the CAD files.

The idea is to start from a blank Ocean™ scene (which can be called a “LOADER”) and then proceed with an external link import of the files from the CAD. In this way, all subsequent modifications made in Ocean™ will be saved in the so-called “LOADER” file and no longer in the CAD geometry files. We’re free to make CAD updates without the risk of deleting Ocean™ scene properties.

Bringing in the elements: How to import files/objects into Ocean™

In Ocean™, we can import existing Ocean™ files (ocxml/ocbin). This is not the same as importing other standard file formats. The method of importing one file into another allows us to assemble elements from one Ocean™ scene to another.

For example, in one scene, you can import a new camera/instrument from another project. This makes it possible to re-use existing elements without having to create them from scratch.

There are 2 types of import:

Import files by merging
Import external files

The first method allows you to integrate one element definitively into another. This is known as merging imported elements.

The second method creates a link between imported elements and the scene, but without merging them. So, when an element is modified, Ocean™ synchronizes it with the scene. The result is a dynamic relationship between the two elements.

Building a virtual structure: A standard physically true architectural scene in Ocean™

Let’s assume we have a standard physically true architectural scene in Ocean™. The main parts are as follows:

The building and all its elements (wall, windows, glazing, balcony, curtains). A large ground as a land to fill the stage. Some trees for vegetation. A few people. A background to fill the horizon. An environment (sunny sky, cloudy sky …) to light the scene and set the mood.

Method #1 – When to use single-file loading in Ocean™

One method is to export the entire project from CAD in one go. A single Ocean™ loader imports the geometries (CAD) and manages all the properties of the Ocean™ scene. We can edit the properties of the Ocean™ scene without altering the CAD.

However, this method (which is possible) could be rather cumbersome to manage, due to the complexity of the vegetation and people (many triangles).

Understanding the pros and cons of single-file loading

The big advantage of this method is that the entire project is accessible from a single CAD file, making it easier to maintain as the project progresses and iterates.

However, the major disadvantage is these iterations mean that the CAD geometries need to be updated regularly. Each time a CAD is exported, a certain amount of processing time is required to export the scene, especially if it’s a heavy one. If we need to modify a small element in the scene, we’ll have to export the whole scene again to take this small change into account. Furthermore, Ocean™ loads the entire scene for each simulation. Therefore, to progress with the project gradually, it may be a good idea to split the scene into several different parts. The necessary elements are loaded, then the others can be put on hold until each stage has been completed.

Method #2 – Optimizing performance: A multi-file approach to Ocean™ scenes

Now, the project is divided into several files, each of which is exported. We can create a loader for each configuration of our project. Each loader imports all the elements required for the desired configuration. For speed and optimization purposes, we can avoid importing specific files (e.g. large vegetation, people), thus reducing the loading time of the project.

For this particular project, we wanted to re-use elements such as the ground, the background horizon, and several environments. The main building is exported from Rhino. People and trees, each originating from a single instance, are duplicated and distributed via 3DSmax to populate and create a forest. The background horizon was created a long time ago from another project, then used again in this project without further modification. The ground is made up of a large flat circle drawn in Rhino, also from another project, and we’re reusing it as is, changing its material later in Ocean™ if necessary.

By splitting the scene into several elements, we can later add further elements such as interior furniture, interior lighting, some vehicles on the outside to create a more immersive preview…

Efficiency through structure: Managing files and folders in Ocean™

In our project folder, we have a pre-made Ocean™ file containing several environments as a library. The same goes for some standard materials.

Geometry elements are exported in a subdirectory and, for each one, in a directory named after them, with all their dependency files (textures) if required. This makes it easy to update each element independently of the others.
Now you can create as many loaders as you like for each scene configuration. By importing only CAD building geometries, you can focus on their materials.

Conclusion:

Ocean™ can be versatile in managing both simple and complex physico-realistic scenes. Consider importing CAD elements rather than opening them, to gain greater flexibility in managing your Ocean™ scene and to make it easier to update these elements without interfering with the scene settings.
For a complex or large-scale scene, it’s a good practice to separate the most important elements, to better distribute the workload over time.

The import workflow provides architects and project developers across multiple industries with a dynamic canvas to quickly test and refine their designs. By importing CAD elements, users can prototype and iterate within Ocean™ and gain insight into lighting, materials and overall scene dynamics in a virtual space. This improves decision-making and accelerates the design iteration process by providing a realistic and immersive preview of complex projects.

All simulations displayed in this article were generated with Ocean™.

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