String inputPath = "sample.stl";
if (!Files.isReadable(Paths.get(inputPath))) {
    System.err.println("Input STL file not found or not readable: " + inputPath);
    return;
}

try (Converter converter = new Converter(inputPath)) {
    // conversion logic follows
}

// LoadOptions loadOptions = new StlLoadOptions();
// converter.setLoadOptions(loadOptions);

PdfConvertOptions pdfOptions = new PdfConvertOptions();
pdfOptions.setPageSize(PdfPageSize.A4);
pdfOptions.setPageOrientation(PdfPageOrientation.PORTRAIT);
pdfOptions.setQuality(100);
pdfOptions.setEmbedFonts(true);
pdfOptions.setOptimizeForPrint(true);
pdfOptions.setCompressImages(true);

converter.convert("sample.pdf", pdfOptions);
File pdfFile = new File("sample.pdf");
if (pdfFile.exists() && pdfFile.length() > 0) {
    System.out.println("Generated PDF is valid. Size: " + pdfFile.length() + " bytes.");
}

import com.groupdocs.conversion.Converter;
import com.groupdocs.conversion.enums.PdfPageOrientation;
import com.groupdocs.conversion.enums.PdfPageSize;
import com.groupdocs.conversion.options.convert.PdfConvertOptions;
import com.groupdocs.conversion.options.load.LoadOptions;
import com.groupdocs.conversion.options.load.StlLoadOptions;

import java.io.File;
import java.nio.file.Files;
import java.nio.file.Paths;

public class StlToPdfDemo {
    public static void main(String[] args) {
        // Input STL file and desired PDF output file
        String inputPath = "sample.stl";
        String outputPath = "sample.pdf";

// Verify that the input file exists and is readable
        if (!Files.isReadable(Paths.get(inputPath))) {
            System.err.println("Input STL file not found or not readable: " + inputPath);
            return;
        }

// Perform conversion inside a try‑with‑resources block to guarantee cleanup
        try (Converter converter = new Converter(inputPath)) {
            // If STL‑specific loading options are required, uncomment the following lines:
            // LoadOptions loadOptions = new StlLoadOptions();
            // converter.setLoadOptions(loadOptions);

// Configure PDF conversion options
            PdfConvertOptions pdfOptions = new PdfConvertOptions();
            pdfOptions.setPageSize(PdfPageSize.A4);
            pdfOptions.setPageOrientation(PdfPageOrientation.PORTRAIT);
            pdfOptions.setQuality(100);                 // Highest visual quality
            pdfOptions.setEmbedFonts(true);             // Ensure fonts are embedded
            pdfOptions.setOptimizeForPrint(true);       // Optimize PDF for printing
            pdfOptions.setCompressImages(true);         // Reduce PDF size without quality loss

// Execute the conversion
            converter.convert(outputPath, pdfOptions);
            System.out.println("STL to PDF conversion completed successfully: " + outputPath);
        } catch (Exception ex) {
            System.err.println("An error occurred during conversion:");
            ex.printStackTrace();
            return;
        }

// Simple validation of the generated PDF
        File pdfFile = new File(outputPath);
        if (pdfFile.exists() && pdfFile.length() > 0) {
            System.out.println("Generated PDF is valid. Size: " + pdfFile.length() + " bytes.");
        } else {
            System.err.println("PDF generation failed or resulted an empty file.");
        }
    }
}

<repositories>
    <repository>
        <id>conholdate-repo</id>
        <name>Conholdate Maven Repository</name>
        <url>https://repository.conholdate.com/repo/</url>
    </repository>
</repositories>

<dependency>
    <groupId>com.conholdate</groupId>
    <artifactId>conholdate-total</artifactId>
    <version>24.9</version>
    <type>pom</type>
</dependency>