This article shows how to use the basic ‘Speos Sphere’ model to simulate and visualize the effect of changing materials.
Prerequisites
- Speos 25R1 or later
- Speos material library
- Speos Sphere model
Overview
The ‘Speos Sphere’ model can be utilized for initial visualization to see how various materials can affect visual appearance. Instead of using existing complex project models for appearance evaluation, this model can be utilized for quick appearance assessment. The article will also show how to leverage embedded material libraries and live preview, powered by GPU, to improve user experience and to gather faster results.
Material Libraries
Creating material libraries inside Speos allows users to organize optical property data. The optical property data can be organized based on user’s needs e.g. alphabetically, based on material like glass, plastic or based on volume properties, surface properties or based on material supplier names etc. This makes it convenient to sort and reuse the in-house optical material data for future projects.
Texture mapping
In reality, most materials have textures such as stickers, grained materials (plastic, leather) etc. Texture mapping is a process that allows users to simulate material texture to generate realistic appearance. Texture mapping has two important components UV mapping feature and texture itself.
The texture itself is flat/2D, but the geometry is usually 3D. UV mapping allows texture to be wrapped on the geometry in planner, cubical, cylindrical or spherical. Texture is what you want to apply on geometry to create a realistic appearance. Texture can be an image, image with normal map, or a texture related to an optical property.
Speos provides multi surface layer mode which allows to combine and superimpose several texture layers for achieving realistic appearance
AxF Files
AxF (Appearance eXchange Format) files are textured appearance property files generated by X-Rite measurement devices. From 25R1 and onward, AxF files in SVBRDF material format are compatible with Speos.
Traditional BRDF format is created from raw measurements. This is especially useful for optical system design because
- It is fully spectral --> compute radiometry and photometry, IR to UV
- Energy conserving --> energy out + absorption = energy in
- Respecting Helmholtz reciprocity --> same results in direct and inverse simulation
However, AxF file format is based on SVBRDF which may not meet above requirements all the time. For appearance evaluation, the previous characteristics may or may not be required depending on the user's application. Creating a highly complex environment (indoor or outdoor) for scene inside Speos using traditional BRDF can be time consuming and tedious. AxF plays important roles to fill this gap where only appearance is of a concern and not photometry. AxF file formats are widely used in automotive industry for visual evaluation of interior and exterior of cars in early stages.
Speos simulation with AxF material for interior appearance evaluation
Live Preview
Speos Live Preview allows to compute the simulation using GPU available on the user’s computer . Live Preview traces the rays on the go and generates the result instantaneously . As the number of rays traced increases, so does the quality of result. Live Preview lets a user see the effect of modifying the input parameters on the result immediately. This can be useful in early stages to evaluate multiple design solutions rather quickly. Live Preview saves time by allowing efficient iterative optimization in real time.
Workflow
Step 1: Initial Setup
Open the ‘SpeosSphere2025R1_Reference.scdocx’ file. Go to simulation tab and rerun the simulation ‘Inverse Studio Environment’. GPU compute can be used for faster results if the system has dedicated NVidia graphic processor.
Initial result for inverse simulation
Step 2: Material selection and application
- Go to Programs (Window key from keyboard) --> Ansys 2025 R1 --> Speos Materials 2025 R1. It will open the folder containing embedded speos material library. Copy the path of the folder.
- Now go to Light Simulation tab --> Material Libraries. It will create a new tab at the bottom as shown. Go to Libraries tab and click on
open a library file to specify the material library path copied above.
- Go to Optical_Property and click on Surface PAINT.sml file.
- Click on the Locate Materials from Light Simulation tab and then click on Search for applied materials in space claim environment. Now move the cursor on the Speos Sphere which will highlight the material that is currently in use which is MAIN MATERIAL
- Go to Simulation tab Materials MAIN MATERIAL to locate the material
- Now drag and drop CAR-PAINT-MescalitoBlack 1600 material from Libraries to MAIN MATERIAL in simulation. By dragging and dropping new material, it is automatically applied to all the geometries which had previous material.
Step 3: Result
Rerun the inverse simulation to get the updated result. This way various materials can be applied to check the appearance quickly, saving some crucial time in early stages of the project.
Step 4: Tips and tricks
- The above mentioned method works but what if there is an even faster way to get the result when you are going through lots of material. Don’t worry, we got that covered.
- Click on the ‘Inverse Studio environment’ from simulation tree. Go to Light Simulation tab --> Preview to open the Live Preview window. Speos Live Preview allows you to compute the simulation using progressive rendering with the most powerful GPU available on your computer and displays the result in a dedicated window calculated in real-time.
- Now go back to Material Library --> Fabric --> Fabric Coarse red. Drag and drop this new material on previously applied ‘CAR-PAINT-MescalitoBlack 1600’. You may have to move Live Preview window to one side to see below message. Click OK.
- To activate Beta features, go to Files -> Speos Option -> Advanced -> Enable beta features
- Go to Light Simulation tab --> Update Preview button will be activated now. Click on Update Preview button to see real time simulation result.
- Updated result
- For even faster results, sensor resolution and/or Stop Conditions for simulation can be reduced
Taking the model further
Importing AxF Files
As discussed previously, AxF files are very useful for appearance evaluation and can save crucial time when creating an environment inside Speos.
Create new material and select the geometries that it will be applied to. Set ‘Use texture’ to ‘True’ to create a surface layer. In Surface layer select ‘Type’ as ‘Appearance’ to import AxF Files